|
%I #14 Dec 07 2016 12:36:36
%S 1122659,2164229,2329469,10257809,10309889,12314699,14030309,14145539,
%T 19099919,23103659,24176129,28843649,37088729,38199839,42389519,
%U 49160099,50785439,52554569,62800169,68718059,85864769,88174049,95831189,105109139,105388169
%N Numbers n such that n remains prime through 6 iterations of function f(x) = 2x + 1.
%C n, 2*n+1, 4*n+3, 8*n+7, 16*n+15, 32*n+31, and 64*n+63 are primes.
%C a(n) == 29 (mod 30).
%o (PARI) a005408(n) = 2*n+1
%o count(n) = my(k=n, i=0); while(ispseudoprime(k), k=a005408(k); i++); i
%o is(n) = count(n) > 6 \\ _Felix Fröhlich_, Dec 05 2016
%Y Subsequence of A007700, A023272, A023302, and A023330.
%K nonn
%O 1,1
%A _John Cerkan_, Dec 01 2016
|
