A050454 a(n) = Sum_{d|n, d=3 mod 4} d^3.

0, 0, 27, 0, 0, 27, 343, 0, 27, 0, 1331, 27, 0, 343, 3402, 0, 0, 27, 6859, 0, 370, 1331, 12167, 27, 0, 0, 19710, 343, 0, 3402, 29791, 0, 1358, 0, 43218, 27, 0, 6859, 59346, 0, 0, 370, 79507, 1331, 3402, 12167, 103823, 27, 343, 0, 132678, 0, 0

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

A050454 := proc(n) local a,d; a := 0 ; for d in numtheory[divisors](n) do if d mod 4 = 3 then a := a+d^3 ; end if; end do; a ; end proc:
seq(A050454(n),n=1..100) ; # R. J. Mathar, Jan 07 2011

Mathematica

a[n_] := DivisorSum[n, #^3 &, Mod[#, 4]==3 &]; Array[a, 30] (* Amiram Eldar, Dec 06 2018 *)
Table[Total[Select[Divisors[n],Mod[#,4]==3&]^3],{n,80}] (* Harvey P. Dale, Oct 13 2024 *)