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

1,1

Links

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

Formula

a(n) = A008472(A055394(n)).

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 *)

Crossrefs

Cf. A008472, A055394, A078377, A078382, A078384.

Sequence in context: A358923 A328827 A181184 * A232644 A125512 A272908

Adjacent sequences: A078380 A078381 A078382 * A078384 A078385 A078386

Keyword

nonn

Author

Reinhard Zumkeller, Nov 25 2002

Status

approved