A050451 a(n) = Sum_{d|n, d=1 mod 4} d^3.

1, 1, 1, 1, 126, 1, 1, 1, 730, 126, 1, 1, 2198, 1, 126, 1, 4914, 730, 1, 126, 9262, 1, 1, 1, 15751, 2198, 730, 1, 24390, 126, 1, 1, 35938, 4914, 126, 730, 50654, 1, 2198, 126, 68922, 9262, 1, 1, 91980, 1, 1, 1, 117650, 15751, 4914, 2198, 148878

Offset: 1

Author

N. J. A. Sloane, Dec 23 1999

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Programs

Maple

A050451 := proc(n) local a,d; a := 0 ; for d in numtheory[divisors](n) do if d mod 4 = 1 then a := a+d^3 ; end if; end do; a ; end proc:
seq(A050451(n),n=1..100) ; # R. J. Mathar, Jan 07 2011

Mathematica

a[n_] := DivisorSum[n, #^3 &, Mod[#, 4]==1 &]; Array[a, 30] (* Amiram Eldar, Dec 06 2018 *)