Block #379,976

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 1/28/2014, 10:03:11 PM · Difficulty 10.4175 · 6,429,979 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
d93db2bd710e24c504de8c60dced8ede2bfc1f037ba957f6ef1b4bf4f2e24fcb

Height

#379,976

Difficulty

10.417535

Transactions

1

Size

971 B

Version

2

Bits

0a6ae38f

Nonce

38,080

Timestamp

1/28/2014, 10:03:11 PM

Confirmations

6,429,979

Merkle Root

7d11b9c6b2e31287d86a03b86f1f828f29862c9b918598f414dbe6d22a648953
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.

7.650 × 10⁹⁹(100-digit number)
76502263870803228287…23400157122641511999
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
7.650 × 10⁹⁹(100-digit number)
76502263870803228287…23400157122641511999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.530 × 10¹⁰⁰(101-digit number)
15300452774160645657…46800314245283023999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.060 × 10¹⁰⁰(101-digit number)
30600905548321291315…93600628490566047999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
6.120 × 10¹⁰⁰(101-digit number)
61201811096642582630…87201256981132095999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.224 × 10¹⁰¹(102-digit number)
12240362219328516526…74402513962264191999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.448 × 10¹⁰¹(102-digit number)
24480724438657033052…48805027924528383999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
4.896 × 10¹⁰¹(102-digit number)
48961448877314066104…97610055849056767999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
9.792 × 10¹⁰¹(102-digit number)
97922897754628132208…95220111698113535999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.958 × 10¹⁰²(103-digit number)
19584579550925626441…90440223396227071999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
3.916 × 10¹⁰²(103-digit number)
39169159101851252883…80880446792454143999
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:57,723,721 XPM·at block #6,809,954 · updates every 60s
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