221375domain: NAppears in sequencesDegrees of irreducible representations of Conway group Co2.at n=28A003911Odd hexagonal pyramidal numbers.at n=34A015225Numbers n such that n^2 can be split into two nonzero squares (perhaps with leading zeros) in exactly two different ways.at n=18A054737a(n) = binomial(n+2,3)*5^3.at n=20A141480