Primes p such that p^2 divides 18^(p-1) - 1.A244260Primes p such that p^2 divides 18^(p-1) - 1.Terms a(0) =5a(1) =7a(2) =37a(3) =331a(4) =33923a(5) =1284043External referencesoeis: A244260