cp's OEIS Frontend

A078377 Number of distinct prime factors of numbers which can be written as sum of a positive square and a positive cube.

%I A078377 #9 Mar 27 2025 04:27:46
%S A078377 1,1,1,2,2,1,2,2,2,1,2,2,1,1,2,2,2,2,2,2,2,2,1,2,2,2,1,2,2,1,2,1,2,3,
%T A078377 1,1,2,2,2,2,2,3,2,2,2,3,2,3,2,2,2,2,1,3,2,2,2,3,1,2,2,2,1,1,3,3,1,3,
%U A078377 3,2,1,3,1,1,3,3,2,2,2,2,2,2,1,2,1,3,2,2,1,1,3,2,2,2,1,2,3,2,2,1,2,3,2,3,2
%N A078377 Number of distinct prime factors of numbers which can be written as sum of a positive square and a positive cube.
%H A078377 Amiram Eldar, <a href="/A078377/b078377.txt">Table of n, a(n) for n = 1..10000</a>
%F A078377 a(n) = A001221(A055394(n)).
%t A078377 PrimeNu[Select[Range[200], Length[Reduce[a^2 + b^3 == # && a > 0 && b > 0, {a, b}, Integers]] > 0 &]] (* _Amiram Eldar_, Mar 27 2025 *)
%Y A078377 Cf. A001221, A055394, A078378, A078379.
%K A078377 nonn
%O A078377 1,4
%A A078377 _Reinhard Zumkeller_, Nov 25 2002