Block #2,949,814

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 12/3/2018, 5:44:35 AM · Difficulty 11.3968 · 3,895,564 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
77d18dcae5290c056552e46423ed321167b272c9a2589375fb20c91b4076975b

Height

#2,949,814

Difficulty

11.396811

Transactions

32

Size

8.92 KB

Version

2

Bits

0b659560

Nonce

1,894,791,078

Timestamp

12/3/2018, 5:44:35 AM

Confirmations

3,895,564

Merkle Root

a56757f96e9586ee0065c5b2fd2cead93f9fe9701db8446bd4c5e7f654d805eb
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.

6.200 × 10⁹³(94-digit number)
62001472402260566998…83918734802735310429
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
6.200 × 10⁹³(94-digit number)
62001472402260566998…83918734802735310429
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.240 × 10⁹⁴(95-digit number)
12400294480452113399…67837469605470620859
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.480 × 10⁹⁴(95-digit number)
24800588960904226799…35674939210941241719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.960 × 10⁹⁴(95-digit number)
49601177921808453598…71349878421882483439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
9.920 × 10⁹⁴(95-digit number)
99202355843616907197…42699756843764966879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.984 × 10⁹⁵(96-digit number)
19840471168723381439…85399513687529933759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.968 × 10⁹⁵(96-digit number)
39680942337446762878…70799027375059867519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
7.936 × 10⁹⁵(96-digit number)
79361884674893525757…41598054750119735039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.587 × 10⁹⁶(97-digit number)
15872376934978705151…83196109500239470079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
3.174 × 10⁹⁶(97-digit number)
31744753869957410303…66392219000478940159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
6.348 × 10⁹⁶(97-digit number)
63489507739914820606…32784438000957880319
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:58,007,469 XPM·at block #6,845,377 · updates every 60s
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