

A239008


Exponents m such that the decimal expansion of 3^m exhibits its first zero from the right later than any previous exponent.


7



0, 3, 5, 7, 9, 11, 13, 19, 23, 24, 26, 28, 31, 34, 52, 65, 68, 136, 237, 4947, 7648, 42073, 50693, 52728, 395128, 2544983, 6013333, 76350564, 160451107, 641814146, 5291528429, 5856442430, 7307126644, 11577159988
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OFFSET

1,2


COMMENTS

Assume that a zero precedes all decimal expansions. This will take care of those cases in A030700.
Inspired by the Seqfan list discussion Re: "possible sequence", beginning with David Wilson 7:57 PM Mar 06 2014 and continued by M. F. Hasler, Allan Wechsler and Franklin T. AdamsWatters.
Highest position known at present is 230th digit from the right for a(34).  Bert Dobbelaere, Jan 21 2019


LINKS

Table of n, a(n) for n=1..34.


EXAMPLE

Obviously a(1) is 0. a(2) is 3 since this is the first exponent which yields a twodigit (nonzero) power of three.


MATHEMATICA

f[n_] := Position[ Reverse@ Join[{0}, IntegerDigits[ PowerMod[3, n, 10^500]]], 0, 1, 1][[1, 1]]; k = 1; mx = 0; lst = {}; While[k < 200000001, c = f[k]; If[c > mx, mx = c; AppendTo[ lst, k]; Print@ k]; k++]; lst


CROSSREFS

Cf. A000244, A030700, A020665, A031142, A239009, A239010, A239011, A239012, A239013, A239014, A239015.
Sequence in context: A062090 A172095 A133854 * A291343 A030155 A143448
Adjacent sequences: A239005 A239006 A239007 * A239009 A239010 A239011


KEYWORD

nonn,base,more


AUTHOR

Charles R Greathouse IV and Robert G. Wilson v, Mar 14 2014


EXTENSIONS

a(30)a(34) from Bert Dobbelaere, Jan 21 2019


STATUS

approved



