Block #462,938

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/27/2014, 6:28:52 PM · Difficulty 10.4171 · 6,348,040 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
25bb384ac417bb6b67c3b6cbc1ed0e60f8eeaceff5ac608399d4837b3ed02577

Height

#462,938

Difficulty

10.417084

Transactions

4

Size

2.21 KB

Version

2

Bits

0a6ac603

Nonce

4,978

Timestamp

3/27/2014, 6:28:52 PM

Confirmations

6,348,040

Merkle Root

7f6ccd2edebbbebcd76eeabac855a9899cf85d52f065fb72a83b91dee95e7b91
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.

2.837 × 10⁹⁴(95-digit number)
28377599306074888863…30172211512524474721
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
2.837 × 10⁹⁴(95-digit number)
28377599306074888863…30172211512524474721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.675 × 10⁹⁴(95-digit number)
56755198612149777726…60344423025048949441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.135 × 10⁹⁵(96-digit number)
11351039722429955545…20688846050097898881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.270 × 10⁹⁵(96-digit number)
22702079444859911090…41377692100195797761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.540 × 10⁹⁵(96-digit number)
45404158889719822181…82755384200391595521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.080 × 10⁹⁵(96-digit number)
90808317779439644362…65510768400783191041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.816 × 10⁹⁶(97-digit number)
18161663555887928872…31021536801566382081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.632 × 10⁹⁶(97-digit number)
36323327111775857744…62043073603132764161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.264 × 10⁹⁶(97-digit number)
72646654223551715489…24086147206265528321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.452 × 10⁹⁷(98-digit number)
14529330844710343097…48172294412531056641
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:57,731,927 XPM·at block #6,810,977 · updates every 60s
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