A078379 Minimum exponent in prime factorization of numbers which can be written as sum of a positive square and a positive cube.

1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1

Offset

1,3

Links

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

Formula

a(n) = A051904(A055394(n)).

Mathematica

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

Crossrefs

Cf. A051904, A055394, A078378, A078379, A078380.

Sequence in context: A039737 A144382 A139553 * A121657 A043282 A031226

Adjacent sequences: A078376 A078377 A078378 * A078380 A078381 A078382

Keyword

nonn

Author

Reinhard Zumkeller, Nov 25 2002

Status

approved