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%I #9 Nov 07 2013 05:14:33
%S 5087,11173,16657,47017,54503,185243,207643,300413,306167,341813,
%T 391387,849047,1348577,1438223,1502923,1857407,1909267,2121737,
%U 2161163,2288773,2610133,2725157,2744723,2779097,2874463,2881327
%N Primes p that remain prime through at least 3 iterations of function f(p)=p^2+4.
%H Zak Seidov, <a href="/A116887/b116887.txt">Table of n, a(n) for n = 1..2568</a> All terms up to 10^10.
%e p=5087, f(p)= 25877573, f(f(p))= 669648784370333 and f(f(f(p)))= 448429494408664742387290530893 are all primes.
%t Select[Prime[Range[8! ]],PrimeQ[ #^2+4]&&PrimeQ[(#^2+4)^2+4]&&PrimeQ[ ((#^2+4)^2+4)^2+4]&] [_Vladimir Joseph Stephan Orlovsky_, Feb 26 2010]
%Y Cf. A062324, A116886, A116888, A116889.
%K nonn
%O 1,1
%A _Giovanni Resta_, Feb 27 2006
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