A131613 Numbers k such that the decimal expansion of 3^k contains no 9.

0, 1, 3, 4, 5, 7, 8, 11, 12, 16, 19, 20, 21, 29, 32, 56

Offset: 1

Author

Shyam Sunder Gupta, Sep 01 2007

Keywords

• base
• fini
• nonn

Comments

I conjecture that 56 is the last term.

Crossrefs

Numbers k such that the decimal expansion of 3^k contains no m: A030700 (m=0), A131627 (m=1), A131625 (m=2), A131629 (m=3), A131618 (m=4), A131617 (m=5), A131616 (m=6), A131615 (m=7), A131614 (m=8), this sequence (m=9).

Cf. A007377.

Programs

Magma

[n: n in [0..1000] | not 9 in Intseq(3^n) ]; // Vincenzo Librandi, May 06 2015

Mathematica

Join[{0}, Select[ Range@10000, FreeQ[ IntegerDigits[3^# ], 9] &]]

Extensions

Adapted Mma and initial 0 added by Vincenzo Librandi, May 06 2015