42959domain: NAppears in sequencesA Fielder sequence.at n=15A001649Numbers k such that 5*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=13A056713Expansion of Product_{k>=1} (1 + (x + x^2)^k).at n=17A266108Numbers k such that sigma(k) = psi(k) + tau(k)^2.at n=37A390296