A228865 - OEIS

%I #7 Sep 10 2013 05:04:19

%S 5,11,53,149,331,449,1307,1381,1777,2039,2719,3041,3617,3739,4243,

%T 4643,4919,6263,7079,9049,9629,12799,16931,18257,20483,21059,24061,

%U 32441,32803,34267,38069,42071,46703,49331,53411,57173,64063,68699,74587,75683,105691,110291

%N Primes of the form n^2 + pi(n).

%C Conjecture: the sequence is infinite.

%H K. D. Bajpai, <a href="/A228865/b228865.txt">Table of n, a(n) for n = 1..2000</a>

%e a(6)= 449 which is a prime. 21^2+pi(21) = 441 + 8 = 449.

%p with(numtheory): KD:= proc() local a,b;  a:= n^2+pi(n); if isprime(a) then RETURN(a): fi; end: seq(KD(),n=1..1000);

%Y Cf. A076757

%K nonn

%O 1,1

%A _K. D. Bajpai_, Sep 05 2013