A035062 Numbers n such that 2^n does not contain the digit 7.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 19, 22, 23, 25, 28, 33, 41, 42, 49, 50, 54, 61, 71

Offset

1,3

Comments

It is conjectured that 71 is the last term.

Links

Table of n, a(n) for n=1..30.

Mathematica

Join[{0}, Select[ Range@10000, FreeQ[ IntegerDigits[2^# ], 7] &]] (* Shyam Sunder Gupta, Sep 01 2007 *)

Prog

(Magma) [n: n in [0..1000] | not 7 in Intseq(2^n) ]; // Vincenzo Librandi, May 06 2015
(PARI) is(n)=!#select(k->k==7, Set(digits(2^n))) \\ Charles R Greathouse IV, May 06 2015

Crossrefs

Cf. similar sequences listed in A035064.

Sequence in context: A061773 A125007 A290748 * A032964 A033066 A246075

Adjacent sequences: A035059 A035060 A035061 * A035063 A035064 A035065

Keyword

nonn,base

Author

Patrick De Geest, Nov 15 1998

Extensions

Edited by N. J. A. Sloane, May 21 2008 at the suggestion of R. J. Mathar

Initial 0 added and Mathematica code adapted by Vincenzo Librandi, May 06 2015

Status

approved