Block #1,013,904

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/13/2015, 5:23:41 AM · Difficulty 10.7252 · 5,788,761 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a43fe2f858dd7934b33e2408973a09b3c53bb37161604e3c6429572b8c51b805

Height

#1,013,904

Difficulty

10.725189

Transactions

8

Size

150.43 KB

Version

2

Bits

0ab9a5ff

Nonce

139,302,638

Timestamp

4/13/2015, 5:23:41 AM

Confirmations

5,788,761

Merkle Root

bd4781c1fbdae0fbfcb5ff8bba0396b97572c2c9c77b2849651627ac2af7072c
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.

3.701 × 10⁹²(93-digit number)
37018792925842782218…31102143880938905361
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
3.701 × 10⁹²(93-digit number)
37018792925842782218…31102143880938905361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.403 × 10⁹²(93-digit number)
74037585851685564436…62204287761877810721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.480 × 10⁹³(94-digit number)
14807517170337112887…24408575523755621441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.961 × 10⁹³(94-digit number)
29615034340674225774…48817151047511242881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.923 × 10⁹³(94-digit number)
59230068681348451548…97634302095022485761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.184 × 10⁹⁴(95-digit number)
11846013736269690309…95268604190044971521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.369 × 10⁹⁴(95-digit number)
23692027472539380619…90537208380089943041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.738 × 10⁹⁴(95-digit number)
47384054945078761239…81074416760179886081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.476 × 10⁹⁴(95-digit number)
94768109890157522478…62148833520359772161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.895 × 10⁹⁵(96-digit number)
18953621978031504495…24297667040719544321
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:57,665,339 XPM·at block #6,802,664 · updates every 60s
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