A078384 Sum of all prime factors of numbers which can be written as sum of a positive square and a positive cube.

2, 5, 6, 7, 7, 17, 9, 15, 11, 31, 14, 10, 37, 43, 15, 12, 17, 22, 13, 18, 21, 12, 73, 23, 13, 43, 89, 20, 14, 101, 13, 113, 63, 15, 127, 14, 46, 69, 50, 34, 41, 15, 25, 30, 45, 24, 25, 34, 62, 42, 16, 18, 197, 24, 105, 21, 38, 20, 223, 16, 115, 35, 233, 241, 46, 17, 257, 22

Offset

1,1

Links

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

Formula

a(n) = A001414(A055394(n)).

Mathematica

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

Crossrefs

Cf. A001414, A055394, A078378, A078382, A078383.

Sequence in context: A262368 A198547 A120678 * A057544 A382445 A039239

Adjacent sequences: A078381 A078382 A078383 * A078385 A078386 A078387

Keyword

nonn

Author

Reinhard Zumkeller, Nov 25 2002

Status

approved