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A176864 Numbers k such that A053186(k) is prime.

%I A176864 #9 Dec 14 2018 10:46:53
%S A176864 3,6,7,11,12,14,18,19,21,23,27,28,30,32,38,39,41,43,47,51,52,54,56,60,
%T A176864 62,66,67,69,71,75,77,83,84,86,88,92,94,98,102,103,105,107,111,113,
%U A176864 117,119,123,124,126,128,132,134,138,140,146,147,149,151,155,157,161,163
%N A176864 Numbers k such that A053186(k) is prime.
%C A176864 Numbers of the form p + j^2 where p is prime and p <= 2*j. - _Robert Israel_, Dec 14 2018
%H A176864 Robert Israel, <a href="/A176864/b176864.txt">Table of n, a(n) for n = 1..10000</a>
%e A176864 3-1^2=2, 6-2^2=2, 7-2^2=3, 11-3^2=2, ...
%p A176864 N:= 30: # to get all terms < (N+1)^2
%p A176864 Primes:= select(isprime, [2,seq(i,i=3..2*N,2)]):
%p A176864 seq(op(map(`+`, select(`<=`,Primes, 2*j),j^2)),j=1..N); # _Robert Israel_, Dec 14 2018
%t A176864 lst={};Do[p=n-Floor[Sqrt[n]]^2;If[PrimeQ[p],AppendTo[lst,n]],{n,6!}];lst
%Y A176864 Cf. A053186.
%K A176864 nonn
%O A176864 1,1
%A A176864 _Vladimir Joseph Stephan Orlovsky_, Apr 27 2010