Block #437,536

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/10/2014, 9:11:52 AM · Difficulty 10.3572 · 6,379,404 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b729410a9e1efdc982ee29ccff2c76b30c5b2e1d67d56f2f45877c0a38b5af64

Height

#437,536

Difficulty

10.357190

Transactions

3

Size

9.73 KB

Version

2

Bits

0a5b70c9

Nonce

71,568

Timestamp

3/10/2014, 9:11:52 AM

Confirmations

6,379,404

Merkle Root

6fb98d35ed71263237f8797f78e836d1a7fe8b375a2e9aba358d0335fc7025ae
Transactions (3)
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.

3.788 × 10¹⁰⁰(101-digit number)
37888795472860557563…42998921483608891881
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
3.788 × 10¹⁰⁰(101-digit number)
37888795472860557563…42998921483608891881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.577 × 10¹⁰⁰(101-digit number)
75777590945721115127…85997842967217783761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.515 × 10¹⁰¹(102-digit number)
15155518189144223025…71995685934435567521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.031 × 10¹⁰¹(102-digit number)
30311036378288446050…43991371868871135041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.062 × 10¹⁰¹(102-digit number)
60622072756576892101…87982743737742270081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.212 × 10¹⁰²(103-digit number)
12124414551315378420…75965487475484540161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.424 × 10¹⁰²(103-digit number)
24248829102630756840…51930974950969080321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.849 × 10¹⁰²(103-digit number)
48497658205261513681…03861949901938160641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.699 × 10¹⁰²(103-digit number)
96995316410523027362…07723899803876321281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.939 × 10¹⁰³(104-digit number)
19399063282104605472…15447799607752642561
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:57,779,562 XPM·at block #6,816,939 · updates every 60s
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