Block #59,948

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 7/18/2013, 5:12:00 AM · Difficulty 8.9672 · 6,731,183 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
bfb6b7c8f5c82cc72def2edd90c54ee31c536710bdbfacf51bf511d18d21fb54

Height

#59,948

Difficulty

8.967155

Transactions

5

Size

6.70 KB

Version

2

Bits

08f79774

Nonce

254

Timestamp

7/18/2013, 5:12:00 AM

Confirmations

6,731,183

Merkle Root

fd7b354fa026f50b030c1b2019dd5739464b021da133c0cc5e36a794d3889b78
Transactions (5)
1 in → 1 out12.5100 XPM110 B
51 in → 1 out810.3300 XPM5.72 KB
1 in → 1 out12.4800 XPM158 B
1 in → 1 out12.4600 XPM158 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.

1.891 × 10⁹³(94-digit number)
18915215215789361763…97525335898983973459
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
1.891 × 10⁹³(94-digit number)
18915215215789361763…97525335898983973459
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
3.783 × 10⁹³(94-digit number)
37830430431578723526…95050671797967946919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
7.566 × 10⁹³(94-digit number)
75660860863157447052…90101343595935893839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.513 × 10⁹⁴(95-digit number)
15132172172631489410…80202687191871787679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.026 × 10⁹⁴(95-digit number)
30264344345262978820…60405374383743575359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.052 × 10⁹⁴(95-digit number)
60528688690525957641…20810748767487150719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.210 × 10⁹⁵(96-digit number)
12105737738105191528…41621497534974301439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.421 × 10⁹⁵(96-digit number)
24211475476210383056…83242995069948602879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
4.842 × 10⁹⁵(96-digit number)
48422950952420766113…66485990139897205759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
9.684 × 10⁹⁵(96-digit number)
96845901904841532226…32971980279794411519
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:57,572,984 XPM·at block #6,791,130 · updates every 60s
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