Block #2,459,964

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/6/2018, 8:50:12 AM · Difficulty 10.9547 · 4,384,792 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
09bfc7a55fb292eeaa9d2f4a1e1cb4c897359baf45c01fd083d67f7f43cda338

Height

#2,459,964

Difficulty

10.954676

Transactions

2

Size

870 B

Version

2

Bits

0af4659e

Nonce

880,030,866

Timestamp

1/6/2018, 8:50:12 AM

Confirmations

4,384,792

Merkle Root

3772b8fe3e41212ebb6cd56906666a24e43d71f2a4546ada494bbab16fade9bc
Transactions (2)
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.

3.779 × 10⁹⁵(96-digit number)
37796409129726688447…93897228282077435201
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
3.779 × 10⁹⁵(96-digit number)
37796409129726688447…93897228282077435201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.559 × 10⁹⁵(96-digit number)
75592818259453376894…87794456564154870401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.511 × 10⁹⁶(97-digit number)
15118563651890675378…75588913128309740801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.023 × 10⁹⁶(97-digit number)
30237127303781350757…51177826256619481601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.047 × 10⁹⁶(97-digit number)
60474254607562701515…02355652513238963201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.209 × 10⁹⁷(98-digit number)
12094850921512540303…04711305026477926401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.418 × 10⁹⁷(98-digit number)
24189701843025080606…09422610052955852801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.837 × 10⁹⁷(98-digit number)
48379403686050161212…18845220105911705601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.675 × 10⁹⁷(98-digit number)
96758807372100322425…37690440211823411201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.935 × 10⁹⁸(99-digit number)
19351761474420064485…75380880423646822401
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:58,002,463 XPM·at block #6,844,755 · updates every 60s
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