40620domain: NAppears in sequencesNumber of permutations of length n which avoid the patterns 1234, 2431, 4312.at n=16A116765Numbers k such that Bernoulli number B_{k} has denominator 56786730.at n=6A295598Numbers k >= 1 such that k^2 - r^2 is a repunit (A002275) for some 1 <= r < k.at n=23A389493