Block #548,329

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/16/2014, 10:50:18 PM · Difficulty 10.9590 · 6,278,970 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c836a1d40b698214d004741f37f5bb9ca9745b217495b8e7b89ac3ee7ec1d816

Height

#548,329

Difficulty

10.958962

Transactions

1

Size

697 B

Version

2

Bits

0af57e88

Nonce

134,455

Timestamp

5/16/2014, 10:50:18 PM

Confirmations

6,278,970

Merkle Root

afe062adb9880b6ae454b524508e414dc92c3b22128dcd8190a7084fd1294db1
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.

7.497 × 10⁹⁴(95-digit number)
74975434209089770967…90623203872229072641
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
7.497 × 10⁹⁴(95-digit number)
74975434209089770967…90623203872229072641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.499 × 10⁹⁵(96-digit number)
14995086841817954193…81246407744458145281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.999 × 10⁹⁵(96-digit number)
29990173683635908386…62492815488916290561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.998 × 10⁹⁵(96-digit number)
59980347367271816773…24985630977832581121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.199 × 10⁹⁶(97-digit number)
11996069473454363354…49971261955665162241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.399 × 10⁹⁶(97-digit number)
23992138946908726709…99942523911330324481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.798 × 10⁹⁶(97-digit number)
47984277893817453419…99885047822660648961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.596 × 10⁹⁶(97-digit number)
95968555787634906838…99770095645321297921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.919 × 10⁹⁷(98-digit number)
19193711157526981367…99540191290642595841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.838 × 10⁹⁷(98-digit number)
38387422315053962735…99080382581285191681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
7.677 × 10⁹⁷(98-digit number)
76774844630107925470…98160765162570383361
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,862,502 XPM·at block #6,827,298 · updates every 60s
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