A078386 Squarefree kernels of numbers which can be written as sum of a positive square and a positive cube.

2, 5, 3, 10, 6, 17, 6, 26, 14, 31, 33, 6, 37, 43, 22, 10, 26, 57, 21, 65, 34, 6, 73, 38, 10, 82, 89, 91, 10, 101, 6, 113, 122, 42, 127, 2, 129, 134, 141, 145, 74, 30, 38, 161, 82, 170, 57, 174, 177, 185, 21, 14, 197, 102, 206, 26, 217, 110, 223, 15, 226, 58, 233, 241

Offset

1,1

Links

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

Formula

a(n) = A007947(A055394(n)).

Example

A055394(12) = 3^2+3^3 = 36, a(12) = A007947(A055394(12)) = A007947(36) = A007947(2^2*3^2) = 2*3 = 6.

Mathematica

Times @@ FactorInteger[#][[;; , 1]] & /@ Select[Range[300], Length[Reduce[a^2 + b^3 == # && a > 0 && b > 0, {a, b}, Integers]] > 0 &] (* Amiram Eldar, Mar 27 2025 *)

Crossrefs

Cf. A007947, A055394, A078387.

Sequence in context: A352188 A323637 A349637 * A163254 A277696 A143121

Adjacent sequences: A078383 A078384 A078385 * A078387 A078388 A078389

Keyword

nonn

Author

Reinhard Zumkeller, Nov 25 2002

Status

approved