466176domain: NAppears in sequencesa(n) = 6^n mod n^6.at n=9A066610n^10 mod 10^n.at n=5A087355Growth series for group with presentation < S, T : S^2 = T^3 = (S*T)^11 = 1 >.at n=37A299252a(1) = 1; for n > 1, a(n) = sigma((2^n)-1) - sigma((2^(n-1))-1), where sigma is A000203, the sum of divisors.at n=20A329890