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A050454
a(n) = Sum_{d|n, d=3 mod 4} d^3.
2
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
1,3
LINKS
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 *)
CROSSREFS
Sequence in context: A145336 A271246 A005084 * A277042 A224118 A178737
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 23 1999
STATUS
approved