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
Keywords
Examples
A055394(12) = 3^2+3^3 = 36, a(12) = A007947(A055394(12)) = A007947(36) = A007947(2^2*3^2) = 2*3 = 6.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
-
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 *)