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%I #22 Sep 08 2022 08:46:08
%S 477727,507757,30596497,33145687,36180527,61192997,141339217,
%T 148590307,193394347,297180617,374066267,395534747,398001547,
%U 419795137,488716897
%N Primes p such that p remains prime through 7 iterations of function f(x) = 2*x + 3.
%t Select[Prime[Range[600000]], And@@PrimeQ[NestList[2 # + 3 &, #, 7]] &]
%o (Magma) [p: p in PrimesUpTo(600000000) | forall{i: i in [1..7] | IsPrime(2^i*p+3*(2^i-1))}];
%Y Cf. similar sequences with k iterations: A067076 (k=1), A023242 (k=2), A023273 (k=3), A023303 (k=4), A023331 (k=5), A175160 (k=6), this sequence (k=7).
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Jun 24 2014
%E Inappropriate MAGMA code simplified and other terms added from _Bruno Berselli_, Jun 24 2014
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