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A239015 Exponents m such that the decimal expansion of 11^m exhibits its first zero from the right later than any previous exponent. 7
0, 1, 2, 3, 4, 6, 7, 8, 9, 12, 13, 14, 15, 16, 18, 36, 41, 366, 488, 4357, 69137, 89371, 143907, 542116, 2431369, 5877361, 8966861, 121915452, 123793821, 221788016, 709455085, 1571200127, 2640630712, 6637360862, 64994336645, 74770246842 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Assume that a zero precedes all decimal expansions. This will take care of those cases in A001020.

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. Adams-Watters.

LINKS

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

EXAMPLE

Illustration of initial term, with the 0 enclosed in parentheses:

n, position of 0, 11^a(n)

1, 2, (0)1

2, 3, (0)11

3, 4, (0)121

4, 5, (0)1331

5, 6, (0)14641

6, 7, (0)1771561

7, 8, (0)19487171

8, 9, (0)214358881

9, 10, (0)2357947691

10, 11, (0)3138428376721

11, 12, (0)34522712143931

12, 13, (0)379749833583241

13, 14, (0)4177248169415651

14, 15, (0)45949729863572161

15, 16, (0)5559917313492231481

16, 17, 3091268053287(0)672635673352936887453361

...

- N. J. A. Sloane, Jan 16 2020

MATHEMATICA

f[n_] := Position[ Reverse@ Join[{0}, IntegerDigits[ PowerMod[11, n, 10^500]]], 0, 1, 1][[1, 1]]; k = mx = 0; lst = {}; While[k < 40000001, c = f[k]; If[c > mx, mx = c; AppendTo[ lst, k]; Print@ k]; k++]; lst

CROSSREFS

Cf. A001020, A030706, A020665, A031142, A239008, A239009, A239010, A239011, A239012, A239013, A239014.

Sequence in context: A330108 A330104 A330120 * A030706 A285986 A101883

Adjacent sequences:  A239012 A239013 A239014 * A239016 A239017 A239018

KEYWORD

nonn,base,more

AUTHOR

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

EXTENSIONS

a(28)-a(34) from Bert Dobbelaere, Jan 22 2019

a(35)-a(36) from Chai Wah Wu, Jan 16 2020

STATUS

approved

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Last modified April 19 21:57 EDT 2021. Contains 343117 sequences. (Running on oeis4.)