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A239012
Exponents m such that the decimal expansion of 7^m exhibits its first zero from the right later than any previous exponent.
7
0, 2, 3, 6, 10, 11, 19, 35, 127, 131, 175, 207, 1235, 2470, 2651, 1241310, 1922910, 471056338, 1001431598, 1720335627, 4203146094, 5353516238, 21838571507, 25770284079, 40822793867
OFFSET
1,2
COMMENTS
Assume that a zero precedes all decimal expansions. This will take care of those cases in A030703.
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 C. Wechsler and Franklin T. Adams-Watters.
MATHEMATICA
f[n_] := Position[ Reverse@ Join[{0}, IntegerDigits[ PowerMod[7, n, 10^500]]], 0, 1, 1][[1, 1]]; k = mx = 0; lst = {}; While[k < 500000001, c = f[k]; If[c > mx, mx = c; AppendTo[ lst, k]; Print@ k]; k++]; lst
KEYWORD
nonn,base,more
EXTENSIONS
a(19)-a(22) from Bert Dobbelaere, Jan 21 2019
a(23)-a(25) from Chai Wah Wu, Jan 15 2020
STATUS
approved