A282380 Number of ways to write n as a sum of two unordered nonsquarefree numbers.

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 2, 1, 1, 0, 2, 1, 1, 0, 3, 1, 1, 1, 3, 2, 1, 1, 4, 2, 2, 1, 6, 2, 1, 1, 5, 2, 1, 2, 5, 3, 1, 1, 6, 3, 2, 1, 7, 4, 4, 1, 7, 4, 4, 2, 7, 4, 3, 3, 8, 4, 3, 3, 9, 4, 4, 2, 12, 4, 4, 3, 10, 5, 3, 4, 10, 6, 3, 3, 11, 5, 3, 3, 12, 5, 6, 3, 11, 6, 5, 4, 12, 5, 5, 7, 14, 5, 6, 5, 14, 5, 6

Offset: 1

Author

Altug Alkan, Feb 13 2017

Keywords

• nonn

Examples

			a(16) = 2 because 16 = 4 + 12 and 16 = 8 + 8 are only corresponding solutions.
		

Links

• Altug Alkan, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A013929, A071068.

Programs

PARI

a(n) = sum(k=1, n\2, !issquarefree(k) && !issquarefree(n-k));