A160216 - OEIS

A160216

Primes congruent to 2^k+1 (mod 2^(k+1)), where k is any odd integer >=1.

3, 7, 11, 19, 23, 31, 41, 43, 47, 59, 67, 71, 73, 79, 83, 89, 97, 103, 107, 127, 131, 137, 139, 151, 163, 167, 179, 191, 199, 211, 223, 227, 233, 239, 251, 263, 271, 281, 283, 307, 311, 313, 331, 347, 353, 359, 367, 379, 383, 409, 419, 431, 439, 443, 457, 463

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OFFSET

1,1

COMMENTS

Lim_{x -> inf.} the number of terms < x in A160216/A160215 => 2. - Robert G. Wilson v, May 31 2009

LINKS

Table of n, a(n) for n=1..56.

FORMULA

A000040 \ A160215.

{prime(k) : A023506(k) is odd}. - R. J. Mathar, May 08 2009

MATHEMATICA

fQ[n_] := Mod[ Flatten[ FactorInteger[n - 1]] [[2]], 2] == 1; Select[ Prime@ Range@ 90, fQ@# &] (* Robert G. Wilson v, May 31 2009 *)