A106563 Numbers n such that n^2 is not the sum of two primes.

1, 11, 17, 23, 25, 31, 39, 41, 45, 51, 53, 57, 59, 65, 67, 73, 79, 81, 83, 85, 87, 91, 95, 97, 99, 101, 105, 109, 111, 113, 115, 123, 125, 129, 133, 137, 141, 143, 147, 149, 151, 153, 157, 159, 163, 165, 167, 171, 175, 179, 181, 185, 187, 189, 193, 195, 197, 199, 201

Offset: 1

Author

Alexandre Wajnberg, May 09 2005

Keywords

• nonn

Examples

			a(3)=17 because the third square which is not the sum of two primes (289=17^2) is the 17th one in the succession of the perfect squares (thus: index 17).
		

Crossrefs

Cf. A106544-A106548, A106562-A106564, A106571, A106573-A106575, A106577.

Formula

a(n) = SQRT(A106562(n)).

Extensions

Extended by Ray Chandler, May 12 2005