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Sum of a square and a prime.
6

%I #9 Sep 04 2013 09:27:34

%S 2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,20,21,22,23,24,26,27,28,

%T 29,30,31,32,33,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,

%U 53,54,55,56,57,59,60,61,62

%N Sum of a square and a prime.

%C A002471(a(n))>0; complement of A014090; A143989 is a subsequence. [From _Reinhard Zumkeller_, Sep 07 2008]

%o (PARI) isok(n) = for (i = 0, sqrtint(n), if (isprime(n - i^2), return (1))); 0 \\ _Michel Marcus_, Sep 04 2013

%Y Cf. A058654.

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_.