Block #2,047,361

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/1/2017, 12:51:23 AM · Difficulty 10.6842 · 4,796,679 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
58b106885949ed3ff91694fa5156d5698a4b15a1401f18d6a9a692ffb8b1a99b

Height

#2,047,361

Difficulty

10.684156

Transactions

2

Size

14.29 KB

Version

2

Bits

0aaf24de

Nonce

64,055,733

Timestamp

4/1/2017, 12:51:23 AM

Confirmations

4,796,679

Merkle Root

37776f1f653920359f9da655f119896f96628e720f0bf65294a0fc83f51905dd
Transactions (2)
1 in → 1 out8.9000 XPM109 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.

1.881 × 10⁹⁶(97-digit number)
18813147278542947414…53990145350511114241
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
1.881 × 10⁹⁶(97-digit number)
18813147278542947414…53990145350511114241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.762 × 10⁹⁶(97-digit number)
37626294557085894828…07980290701022228481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.525 × 10⁹⁶(97-digit number)
75252589114171789656…15960581402044456961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.505 × 10⁹⁷(98-digit number)
15050517822834357931…31921162804088913921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.010 × 10⁹⁷(98-digit number)
30101035645668715862…63842325608177827841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.020 × 10⁹⁷(98-digit number)
60202071291337431725…27684651216355655681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.204 × 10⁹⁸(99-digit number)
12040414258267486345…55369302432711311361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.408 × 10⁹⁸(99-digit number)
24080828516534972690…10738604865422622721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.816 × 10⁹⁸(99-digit number)
48161657033069945380…21477209730845245441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.632 × 10⁹⁸(99-digit number)
96323314066139890760…42954419461690490881
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:57,996,689 XPM·at block #6,844,039 · updates every 60s
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