Home/Chain Registry/Block #3,506,055

Block #3,506,055

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/9/2020, 1:44:30 AM · Difficulty 10.9303 · 3,336,903 confirmations

2CC
Cunningham Chain of the Second Kind

A sequence where each prime is double the previous prime minus one.

Block Header
Block Hash
b432f3ebbbc5a830458ec89e7fd70dc638b1f28aa3a17965c8e7e96699291522

Difficulty

10.930293

Transactions

14

Size

75.51 KB

Version

2

Bits

0aee27a9

Nonce

1,250,616,532

Timestamp

1/9/2020, 1:44:30 AM

Confirmations

3,336,903

Merkle Root

a7447005ea4a60772bfb8bcc1bd770d55b9c28f905b1a60ab38ac02b50bb51ac
Transactions (14)
1 in → 1 out9.3800 XPM110 B
50 in → 1 out199.9200 XPM7.27 KB
50 in → 1 out199.9200 XPM7.26 KB
50 in → 1 out199.9200 XPM7.27 KB
50 in → 1 out199.9200 XPM7.27 KB
50 in → 1 out199.9200 XPM7.27 KB
50 in → 1 out199.9200 XPM7.27 KB
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

9.850 × 10⁹⁴(95-digit number)
98507583376406955324…86633055221429818880
Discovered Prime Numbers
p_k = 2^k × origin + 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

1
origin + 1
9.850 × 10⁹⁴(95-digit number)
98507583376406955324…86633055221429818881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.970 × 10⁹⁵(96-digit number)
19701516675281391064…73266110442859637761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.940 × 10⁹⁵(96-digit number)
39403033350562782129…46532220885719275521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.880 × 10⁹⁵(96-digit number)
78806066701125564259…93064441771438551041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.576 × 10⁹⁶(97-digit number)
15761213340225112851…86128883542877102081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.152 × 10⁹⁶(97-digit number)
31522426680450225703…72257767085754204161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.304 × 10⁹⁶(97-digit number)
63044853360900451407…44515534171508408321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.260 × 10⁹⁷(98-digit number)
12608970672180090281…89031068343016816641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.521 × 10⁹⁷(98-digit number)
25217941344360180563…78062136686033633281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.043 × 10⁹⁷(98-digit number)
50435882688720361126…56124273372067266561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.008 × 10⁹⁸(99-digit number)
10087176537744072225…12248546744134533121
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

View full Prime Chain Discovery page →
★★★☆☆
Rarity
RareChain length 11
How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Verify on a Primecoin Node

Anyone running a Primecoin node can independently verify this block using the following RPC commands. Run these from the primecoin-cli command line or via the debug console in the Primecoin wallet.

1. Get block hash by height
getblockhash 3506055

Returns the block hash for a given block height. Use this to confirm the hash shown above matches the chain.

2. Get full block data
getblock b432f3ebbbc5a830458ec89e7fd70dc638b1f28aa3a17965c8e7e96699291522

Returns the full block header including difficulty, prime chain origin, prime chain type, transaction IDs, and all other fields shown on this page.

How to run these commands: To verify this data independently, open a terminal on your own Primecoin node and run primecoin-cli <command>. Alternatively, open the Primecoin-Qt wallet, go to Help → Debug Window → Console, and type the command directly. The node must be fully synced to this block height for the commands to return results.

Cross-reference on Chainz Explorer

Chainz is an independent Primecoin block explorer. Compare this block's data to verify accuracy.

View Block #3,506,055 on Chainz ↗
Circulating Supply:57,988,017 XPM·at block #6,842,957 · updates every 60s
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