1,1

Also, n such that 1+n^2 is a nontotient (A005277). - T. D. Noe, Sep 13 2007

T. D. Noe, Table of n, a(n) for n=1..1000

a(n) = sqrt(A106564(n)).

a(3)=11 because the third square which is not the difference of two primes (121=11^2) is the 11th one in the succession of the perfect squares (thus index 11).

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

Cf. A067201 (n such that n^2 + 2 is prime).

Sequence in context: A322271 A306289 A136801 * A067291 A286265 A339911

Adjacent sequences: A106568 A106569 A106570 * A106572 A106573 A106574

easy,nonn

Alexandre Wajnberg, May 09 2005

Extended by Ray Chandler, May 12 2005

approved