Block #1,352,537

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/3/2015, 3:04:32 PM · Difficulty 10.7957 · 5,472,300 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
e7bbf1c539503c39bb53834f3ebd69d4951c9c6671ac41355a4238afde881f04

Height

#1,352,537

Difficulty

10.795671

Transactions

8

Size

4.16 KB

Version

2

Bits

0acbb113

Nonce

1,527,604,194

Timestamp

12/3/2015, 3:04:32 PM

Confirmations

5,472,300

Merkle Root

cc2a2ae50520acc557cb1c08bee3c618137a0469e3b9041df2178d8d4b8da4b7
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.

8.089 × 10⁹⁵(96-digit number)
80899089180312814767…61729364090811773441
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
8.089 × 10⁹⁵(96-digit number)
80899089180312814767…61729364090811773441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.617 × 10⁹⁶(97-digit number)
16179817836062562953…23458728181623546881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.235 × 10⁹⁶(97-digit number)
32359635672125125907…46917456363247093761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.471 × 10⁹⁶(97-digit number)
64719271344250251814…93834912726494187521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.294 × 10⁹⁷(98-digit number)
12943854268850050362…87669825452988375041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.588 × 10⁹⁷(98-digit number)
25887708537700100725…75339650905976750081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.177 × 10⁹⁷(98-digit number)
51775417075400201451…50679301811953500161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.035 × 10⁹⁸(99-digit number)
10355083415080040290…01358603623907000321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.071 × 10⁹⁸(99-digit number)
20710166830160080580…02717207247814000641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.142 × 10⁹⁸(99-digit number)
41420333660320161161…05434414495628001281
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,842,776 XPM·at block #6,824,836 · updates every 60s
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