A078381 Number of divisors of numbers which can be written as sum of a positive square and a positive cube.

2, 2, 3, 4, 6, 2, 8, 4, 6, 2, 4, 9, 2, 2, 6, 6, 6, 4, 6, 4, 6, 12, 2, 6, 10, 4, 2, 4, 9, 2, 12, 2, 4, 12, 2, 8, 4, 4, 4, 4, 6, 12, 8, 4, 6, 8, 6, 8, 4, 4, 8, 9, 2, 12, 4, 10, 4, 12, 2, 9, 4, 8, 2, 2, 8, 18, 2, 12, 16, 4, 2, 16, 2, 3, 8, 12, 8, 6, 14, 4, 6, 6, 2, 8, 2, 12, 8, 12, 2, 2, 24, 4, 10, 6, 2

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A000005(A055394(n)).

Mathematica

DivisorSigma[0, Select[Range[200], Length[Reduce[a^2 + b^3 == # && a > 0 && b > 0, {a, b}, Integers]] > 0 &]] (* Amiram Eldar, Mar 27 2025 *)

Crossrefs

Cf. A000005, A055394, A078377, A078378, A078382.

Sequence in context: A060407 A083702 A074077 * A118975 A215644 A288777

Adjacent sequences: A078378 A078379 A078380 * A078382 A078383 A078384

Keyword

nonn

Author

Reinhard Zumkeller, Nov 25 2002

Status

approved