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%I #6 Apr 03 2023 10:36:11
%S 7,10,11,12,15,18,29,35,45,49,51,55,58,65,80,82,84,89,93,95,114,119,
%T 128,130,140,142,149,155,157,160,166,171,173,175,191,192,209,210,218,
%U 235,240,251,262,263,269,280,305,315,321,324,328,337,341,344,345,363,372
%N Indices n for which A168157(n) is prime.
%C If n=primepi(2^k-1) is in this sequence, then A158671(k) is prime. This happens for k=5, 6, 18,... corresponding to n=11, 18, 23000,... (cf. link).
%H C. Caldwell, G. L. Honaker, Editors: <a href="https://t5k.org/curios/page.php?short=18&submitter=Post">Prime curio!: 18</a> by J. Vos Post.
%o (PARI) s=0; for(n=1,999, isprime(n*#(b=binary(prime(n)))-s+=norml2(b)) & print1(n", "))
%K nonn
%O 1,1
%A _M. F. Hasler_, Nov 21 2009
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