A131617 - OEIS

A131617

Numbers k such that the decimal expansion of 3^k contains no 5.

0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 14, 15, 16, 17, 18, 19, 20, 23, 25, 29, 31, 41, 44, 52, 58, 81, 91

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OFFSET

1,3

COMMENTS

I conjecture that 91 is the last term.

LINKS

MATHEMATICA

Join[{0}, Select[ Range@10000, FreeQ[ IntegerDigits[3^# ], 5] &]

PROG

(Magma) [n: n in [0..1000] | not 5 in Intseq(3^n) ]; // Vincenzo Librandi, May 06 2015

CROSSREFS

Cf. similar sequences listed in A131613.

KEYWORD

base,fini,nonn

AUTHOR

EXTENSIONS

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

STATUS

approved