January 16, 2026
Primes over pumps
Primecoin and Cunningham Prime Chains
Primecoin’s math-mining sparks nerd nostalgia and market-cap shade
TLDR: Primecoin uses prime-number chains as the mining puzzle, turning crypto into math class with a prize. The crowd split: nostalgia and curiosity about smart proof-of-work versus snark over its tiny $2.5M market cap, making it a beloved brainy oddball that still struggles to impress traders.
Crypto gets nerdy: Primecoin doesn’t chase dog coins—it hunts chains of prime numbers called Cunningham chains, where each prime is almost double the last (think 2×p ± 1). It’s a proof-of-work system (the puzzle miners solve) that rewards finding these prime chains, even bi‑twin chains too. Commenters didn’t just read; they vibed. k__ showed up like a talent scout asking, “any other innovative PoW?” while the math crowd cheered. Then nostalgia hit hard: MinelloGiacomo fondly recalled building a Primecoin-style blockchain in college using the Jolie language [https://www.jolie-lang.org/], cue the “prof graded my crypto” jokes and proud lab report flexes. But the sentiment took a sharp turn when wslh dropped the reality check: Primecoin’s market cap is only about $2.5M (link). Instantly, the thread split—team “beautiful math, useful work” versus team “cool science project, zero moon.” The mathheads bragged about record-long prime chains and how Primecoin adjusts difficulty by requiring longer chains over time, while skeptics meme’d it as “nerd coin won’t pay rent.” Still, the curiosity is real: crypto proof-of-work that does something brainy instead of pure energy burn? People are intrigued, roasting the price but respecting the puzzle. The mood: brainy love, budget shade, and a surprising amount of college throwbacks.
Key Points
- •Cunningham chains are sequences of primes where each successor is 2p + 1 (first kind) or 2p − 1 (second kind).
- •The longest known first-kind Cunningham chain has length 17; the longest known second-kind chain has length 19.
- •Python code using SymPy verifies the reported chain lengths for specific large starting primes.
- •Bi-twin chains require n−1 to start a first-kind chain and n+1 to start a second-kind chain of the same length.
- •Primecoin’s proof-of-work requires finding (probable) prime chains of specified length, adjusting difficulty by required chain length and defining chain origin relative to the block header hash.