A181484 Numbers k such that no power of 2 can be subtracted from 3^k to make a prime.

36, 40, 66, 124, 162, 170, 179, 182, 184, 198, 206, 212, 214, 230, 262, 288, 302, 356, 358, 368, 393, 402, 406, 448, 456, 468, 493, 546, 586, 666, 676, 683, 686, 690, 702, 718, 724, 738, 752, 760, 785, 844, 854, 862, 866, 870, 882, 884, 888, 904, 918, 980

Offset

1,1

Comments

Zeros of A181483, -1s of A180303.

Odd terms: 179, 393, 493, 683, 785, 1083, 1161, 1181, 1545, ..., . - Robert G. Wilson v, Oct 25 2010

Links

Table of n, a(n) for n=1..52.

Mathematica

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 *)

Crossrefs

Cf. A013604, A014224, A180303, A181483.

Sequence in context: A254836 A067672 A276710 * A060292 A334911 A305942

Adjacent sequences: A181481 A181482 A181483 * A181485 A181486 A181487

Keyword

nonn

Author

Carl R. White, Oct 23 2010

Extensions

a(30) onwards from Robert G. Wilson v, Oct 25 2010

Name clarified by J. Lowell, Aug 21 2020

Status

approved