A239010 Exponents m such that the decimal expansion of 5^m exhibits its first zero from the right later than any previous exponent.

0, 2, 3, 5, 6, 9, 11, 15, 17, 18, 25, 26, 30, 33, 57, 58, 153, 1839, 3290, 4081, 16431, 577839, 2190974, 15167023, 23155442, 24477994, 36290003, 53687441, 62497567, 181850218, 790111167, 872257561, 4531889178, 26964400609, 32626158305, 268600630073

Offset

1,2

Comments

Assume that a zero precedes all decimal expansions. This will take care of those cases in A008839.

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.

Highest position known is 232th digit from the right for a(33). - Bert Dobbelaere, Jan 21 2019

Links

Table of n, a(n) for n=1..36.

Mathematica

f[n_] := Position[ Reverse@ Join[{0}, IntegerDigits[ PowerMod[5, n, 10^500]]], 0, 1, 1][[1, 1]]; k = mx = 0; lst = {}; While[k < 100000001, c = f[k]; If[c > mx, mx = c; AppendTo[ lst, k]; Print@ k]; k++]; lst

Crossrefs

Cf. A000351, A008839, A020665, A031142, A239008, A239009, A239011, A239012, A239013, A239014, A239015.

Sequence in context: A327516 A054639 A123399 * A104738 A319469 A341123

Adjacent sequences: A239007 A239008 A239009 * A239011 A239012 A239013

Keyword

nonn,base

Author

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

Extensions

a(30)-a(33) from Bert Dobbelaere, Jan 21 2019

a(34)-a(36) from Chai Wah Wu, Jan 18 2020

Status

approved