A078383 Sum of distinct prime factors of numbers which can be written as sum of a positive square and a positive cube.
2, 5, 3, 7, 5, 17, 5, 15, 9, 31, 14, 5, 37, 43, 13, 7, 15, 22, 10, 18, 19, 5, 73, 21, 7, 43, 89, 20, 7, 101, 5, 113, 63, 12, 127, 2, 46, 69, 50, 34, 39, 10, 21, 30, 43, 24, 22, 34, 62, 42, 10, 9, 197, 22, 105, 15, 38, 18, 223, 8, 115, 31, 233, 241, 46, 12, 257, 20, 16, 58, 269
Offset: 1
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
-
Mathematica
Total[FactorInteger[#][[;; , 1]]] & /@ Select[Range[300], Length[Reduce[a^2 + b^3 == # && a > 0 && b > 0, {a, b}, Integers]] > 0 &] (* Amiram Eldar, Mar 27 2025 *)