A181484 - OEIS

%I #13 Aug 22 2020 02:37:01

%S 36,40,66,124,162,170,179,182,184,198,206,212,214,230,262,288,302,356,

%T 358,368,393,402,406,448,456,468,493,546,586,666,676,683,686,690,702,

%U 718,724,738,752,760,785,844,854,862,866,870,882,884,888,904,918,980

%N Numbers k such that no power of 2 can be subtracted from 3^k to make a prime.

%C Zeros of A181483, -1s of A180303.

%C Odd terms: 179, 393, 493, 683, 785, 1083, 1161, 1181, 1545, ..., . - _Robert G. Wilson v_, Oct 25 2010

%t fQ[n_] := Block[{k = 0, lmt = Floor@ Log[2, 3^n] +1, m = 3^n}, While[ k < lmt && !PrimeQ[m - 2^k], k++ ]; k == lmt]; Select[ Range@ 995, fQ] (* _Robert G. Wilson v_, Oct 25 2010 *)

%Y Cf. A013604, A014224, A180303, A181483.

%K nonn

%O 1,1

%A _Carl R. White_, Oct 23 2010

%E a(30) onwards from _Robert G. Wilson v_, Oct 25 2010

%E Name clarified by _J. Lowell_, Aug 21 2020