A078376 Greatest prime factor of numbers which can be written as sum of a positive square and a positive cube.

2, 5, 3, 5, 3, 17, 3, 13, 7, 31, 11, 3, 37, 43, 11, 5, 13, 19, 7, 13, 17, 3, 73, 19, 5, 41, 89, 13, 5, 101, 3, 113, 61, 7, 127, 2, 43, 67, 47, 29, 37, 5, 19, 23, 41, 17, 19, 29, 59, 37, 7, 7, 197, 17, 103, 13, 31, 11, 223, 5, 113, 29, 233, 241, 41, 7, 257, 13, 11, 53, 269, 7

Offset

1,1

Links

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

Formula

a(n) = A006530(A055394(n)).

Mathematica

FactorInteger[#][[-1, 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. A006530, A055394, A078375.

Sequence in context: A393703 A249273 A388175 * A226123 A368658 A216052

Adjacent sequences: A078373 A078374 A078375 * A078377 A078378 A078379

Keyword

nonn

Author

Reinhard Zumkeller, Nov 25 2002

Status

approved