177266

Appears in sequences

• Numbers k such that 7*R_(k+2) - 2*10^k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=23A257031
• Triangle T(n,d) read by rows: the number of mixed trees with n>=1 nodes and 0<=d<n arcs.at n=52A335362