2825762domain: NAppears in sequencesa(n) = Sum_{d|n, d==1 (mod 4)} d^4.at n=40A050448Sum of 4th powers of odd divisors of n.at n=40A051001a(n) = (-1)^n * Sum_{2*m + 1 | 2*n + 1} (-1)^m (2*m + 1)^4.at n=20A204342Sum of the 4th powers of the squarefree divisors of n.at n=40A351267