A131615 - OEIS

A131615

Numbers k such that the decimal expansion of 3^k contains no 7.

0, 1, 2, 4, 5, 8, 9, 10, 12, 13, 17, 21, 22, 24, 26, 30, 32, 33, 36, 42, 46, 66, 101

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OFFSET

1,3

COMMENTS

I conjecture that 101 is the last term.

LINKS

MATHEMATICA

Select[ Range@10000, FreeQ[ IntegerDigits[3^# ], 7] &]

PROG

(Magma) [n: n in [0..1000] | not 7 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