18685
domain: N
Appears in sequences
- a(n) = Sum_{d|n} phi(d^3).at n=35A068963
- Numbers n such that the trinomial x^n-x-1 is irreducible over GF(3).at n=32A223938
- 30-gonal numbers: a(n) = n*(14*n-13).at n=37A254474
- The number of distinct positions on an infinite chessboard reachable by the (2,3)-leaper (or zebra) in at most n moves.at n=24A297740
- Repunit pseudoprimes: composite numbers k such that (10^k - 1)/9 == 1 (mod k).at n=46A303608
- Triangle read by rows : inverse of triangle A339207.at n=38A339209