A181516 Primes in A011371.

3, 7, 11, 19, 23, 31, 41, 47, 53, 67, 71, 73, 79, 89, 97, 101, 109, 113, 127, 131, 137, 149, 173, 181, 191, 193, 197, 229, 239, 263, 271, 277, 281, 293, 311, 337, 349, 353, 359, 367, 383, 389, 397, 401, 421, 431, 439, 449, 461, 463, 467, 479, 487, 491, 499

Offset: 1

Author

Vladimir Shevelev, Oct 26 2010

Keywords

• nonn

Comments

Primes p such that 2^p divides some factorial m!, but 2^(p+1) does not divide m!.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A011371.

Programs

Mathematica

f[n_] := n - DigitCount[n, 2, 1]; s={}; Do[If[PrimeQ[(p = f[n])], AppendTo[s, p]], {n, 1, 510, 2}]; s (* Amiram Eldar, Sep 13 2019 *)
Select[Table[n-DigitCount[n,2,1],{n,0,600}],PrimeQ]//Union (* Harvey P. Dale, Oct 10 2020 *)

Extensions

Comment and definition swapped by R. J. Mathar, Oct 29 2010