Block #513,002

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/27/2014, 6:01:22 AM · Difficulty 10.8344 · 6,294,967 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8a5691b8d9d9274432bb8e53beefb092da14322f00570eed267230ada4558380

Height

#513,002

Difficulty

10.834377

Transactions

5

Size

1.67 KB

Version

2

Bits

0ad599b9

Nonce

58,242,046

Timestamp

4/27/2014, 6:01:22 AM

Confirmations

6,294,967

Merkle Root

a7b5926b94d2b1823a90f16a6dde671b1e97ce62ad224d239d608089d2226a79
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.

2.169 × 10¹⁰⁰(101-digit number)
21698940734336866342…07755200346111394561
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
2.169 × 10¹⁰⁰(101-digit number)
21698940734336866342…07755200346111394561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.339 × 10¹⁰⁰(101-digit number)
43397881468673732684…15510400692222789121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.679 × 10¹⁰⁰(101-digit number)
86795762937347465369…31020801384445578241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.735 × 10¹⁰¹(102-digit number)
17359152587469493073…62041602768891156481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.471 × 10¹⁰¹(102-digit number)
34718305174938986147…24083205537782312961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.943 × 10¹⁰¹(102-digit number)
69436610349877972295…48166411075564625921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.388 × 10¹⁰²(103-digit number)
13887322069975594459…96332822151129251841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.777 × 10¹⁰²(103-digit number)
27774644139951188918…92665644302258503681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.554 × 10¹⁰²(103-digit number)
55549288279902377836…85331288604517007361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.110 × 10¹⁰³(104-digit number)
11109857655980475567…70662577209034014721
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:57,707,795 XPM·at block #6,807,968 · updates every 60s
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