84420domain: NAppears in sequencesExpansion of 1/(1 - x^2 - 2 x^3 + x^4).at n=37A122512Positive numbers m such that m^2 - 1 divides 2^m - 1.at n=20A247219Positive numbers m such that m^2 - 1 divides 4^m - 1.at n=33A271842