Block #325,899

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/23/2013, 9:47:32 AM · Difficulty 10.1959 · 6,480,206 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
cdc83592928862b39eecff41500c556f80daa903b487375eb346d268efdaf28d

Height

#325,899

Difficulty

10.195870

Transactions

18

Size

5.63 KB

Version

2

Bits

0a322483

Nonce

139,085

Timestamp

12/23/2013, 9:47:32 AM

Confirmations

6,480,206

Merkle Root

68c7e65e7d13e18b682375c15cfae87cdf727d377cb9031787242ffceec842c4
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.

1.367 × 10⁹⁵(96-digit number)
13678984093377413402…85980682484754535959
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
1.367 × 10⁹⁵(96-digit number)
13678984093377413402…85980682484754535959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.735 × 10⁹⁵(96-digit number)
27357968186754826805…71961364969509071919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
5.471 × 10⁹⁵(96-digit number)
54715936373509653611…43922729939018143839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.094 × 10⁹⁶(97-digit number)
10943187274701930722…87845459878036287679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.188 × 10⁹⁶(97-digit number)
21886374549403861444…75690919756072575359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
4.377 × 10⁹⁶(97-digit number)
43772749098807722889…51381839512145150719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
8.754 × 10⁹⁶(97-digit number)
87545498197615445778…02763679024290301439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.750 × 10⁹⁷(98-digit number)
17509099639523089155…05527358048580602879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
3.501 × 10⁹⁷(98-digit number)
35018199279046178311…11054716097161205759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
7.003 × 10⁹⁷(98-digit number)
70036398558092356622…22109432194322411519
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,692,914 XPM·at block #6,806,104 · updates every 60s
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