204121

Appears in sequences

• Strong pseudoprimes to base 95.at n=33A020321
• Nonnegative numbers n such that n^42 + 42 is prime.at n=20A104111
• Triangle T(n,k), n>=3, 3<=k<=n, read by rows: T(n,k) = number of simple graphs on n labeled nodes, where each maximally connected subgraph consists of a single node or has a unique cycle of length k.at n=26A144212
• Number of solutions to +-1^2 +- 2^2 +- 3^2 +- ... +- n^2 = n.at n=29A348165