Block #3,241,350

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 6/26/2019, 5:45:47 AM · Difficulty 11.0011 · 3,591,974 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b98cf7d8eafdcd1b4fbf36f814e5925cddf53ec3513d85732185e7b2f6f3a2f7

Height

#3,241,350

Difficulty

11.001105

Transactions

2

Size

21.38 KB

Version

2

Bits

0b004871

Nonce

1,101,690,866

Timestamp

6/26/2019, 5:45:47 AM

Confirmations

3,591,974

Merkle Root

b8f67ee53c080fdf09a386484b9e47b565cc97c077a07a86d4aba27e06b2bd1c
Transactions (2)
1 in → 1 out8.4800 XPM110 B
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.

2.556 × 10⁹⁵(96-digit number)
25567733398721572848…50949119560176454721
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
2.556 × 10⁹⁵(96-digit number)
25567733398721572848…50949119560176454721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.113 × 10⁹⁵(96-digit number)
51135466797443145697…01898239120352909441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.022 × 10⁹⁶(97-digit number)
10227093359488629139…03796478240705818881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.045 × 10⁹⁶(97-digit number)
20454186718977258279…07592956481411637761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.090 × 10⁹⁶(97-digit number)
40908373437954516558…15185912962823275521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.181 × 10⁹⁶(97-digit number)
81816746875909033116…30371825925646551041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.636 × 10⁹⁷(98-digit number)
16363349375181806623…60743651851293102081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.272 × 10⁹⁷(98-digit number)
32726698750363613246…21487303702586204161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.545 × 10⁹⁷(98-digit number)
65453397500727226492…42974607405172408321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.309 × 10⁹⁸(99-digit number)
13090679500145445298…85949214810344816641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.618 × 10⁹⁸(99-digit number)
26181359000290890597…71898429620689633281
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.

★★★☆☆
Rarity
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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, …
Circulating Supply:57,910,785 XPM·at block #6,833,323 · updates every 60s
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