A078387 Moebius's mu of numbers which can be written as sum of a positive square and a positive cube.

-1, -1, 0, 1, 0, -1, 0, 1, 0, -1, 1, 0, -1, -1, 0, 0, 0, 1, 0, 1, 0, 0, -1, 0, 0, 1, -1, 1, 0, -1, 0, -1, 1, 0, -1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, -1, 0, -1, 1, 1, 0, 0, -1, 0, 1, 0, 1, 0, -1, 0, 1, 0, -1, -1, -1, 0, -1, 0, 0, 1, -1, 0, -1, 0, -1, 0, 0, 0, 0, 1, 0, 0, -1, 0, -1, 0, 0, 0, -1, -1, 0, 1, 0, 0, -1, 1, -1

Offset: 1

Author

Reinhard Zumkeller, Nov 25 2002

Keywords

• sign

Links

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

Crossrefs

Cf. A008683, A055394, A078386.

Programs

Mathematica

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

Formula

a(n) = A008683(A055394(n)).