A104052 Primes of the form 2^k-5^m, where 2^k/5^m < 2.

3, 7, 971, 18280739

Offset

1,1

Comments

The current entries are generated by (k=3,m=1) or (k=7,m=3), (k=5,m=2), (k=12,m=5) and (k=26,m=11). Another term with 110 digits is created by (k=367,m=158) and an entry with 199 digits by (k=662,m=285). - R. J. Mathar, Feb 13 2013

Links

Table of n, a(n) for n=1..4.

Mathematica

c = Delete[Union[Flatten[Table[Table[If [ (2^n > 5^m) && Floor[2^n/5^m] < 2, Abs[2^n - 5^m], 0], {m, 1, n}], {n, 1, 200}], 1]], 1] d = Delete[Union[Table[If[PrimeQ[c[[n]]], c[[n]], 0], {n, 1, Length[c]}]], 1]

Crossrefs

Sequence in context: A055624 A065244 A012844 * A062625 A175986 A296351

Adjacent sequences: A104049 A104050 A104051 * A104053 A104054 A104055

Keyword

nonn

Author

Roger L. Bagula, Mar 01 2005

Status

approved