Block #100,650

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/6/2013, 6:34:18 AM · Difficulty 9.4342 · 6,726,504 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c7522ac20fc0ed668243462ec00c2c5a32bf56a34253a86d7fbc6b80e3f732ff

Height

#100,650

Difficulty

9.434185

Transactions

3

Size

583 B

Version

2

Bits

096f26c1

Nonce

114,309

Timestamp

8/6/2013, 6:34:18 AM

Confirmations

6,726,504

Merkle Root

4ea91ad70d82f7b18e7c558fa7fc393b6dc61619bf9ceb9979283704dd5f7ee5
Transactions (3)
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.

2.862 × 10⁹⁴(95-digit number)
28624886861108948221…14374287680020593921
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
2.862 × 10⁹⁴(95-digit number)
28624886861108948221…14374287680020593921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.724 × 10⁹⁴(95-digit number)
57249773722217896443…28748575360041187841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.144 × 10⁹⁵(96-digit number)
11449954744443579288…57497150720082375681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.289 × 10⁹⁵(96-digit number)
22899909488887158577…14994301440164751361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.579 × 10⁹⁵(96-digit number)
45799818977774317154…29988602880329502721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.159 × 10⁹⁵(96-digit number)
91599637955548634309…59977205760659005441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.831 × 10⁹⁶(97-digit number)
18319927591109726861…19954411521318010881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.663 × 10⁹⁶(97-digit number)
36639855182219453723…39908823042636021761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.327 × 10⁹⁶(97-digit number)
73279710364438907447…79817646085272043521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.465 × 10⁹⁷(98-digit number)
14655942072887781489…59635292170544087041
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:57,861,416 XPM·at block #6,827,153 · updates every 60s
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