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A044518 Numbers n such that string 5,5 occurs in the base 6 representation of n but not of n+1. 1
35, 71, 107, 143, 179, 215, 251, 287, 323, 359, 395, 431, 467, 503, 539, 575, 611, 647, 683, 719, 755, 791, 827, 863, 899, 935, 971, 1007, 1043, 1079, 1115, 1151, 1187, 1223, 1295, 1331, 1367, 1403, 1439, 1475, 1511, 1547, 1583 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A 6-automatic set: membership is determined by comparing the base-6 representation of the number to the regular expression /5?([^5]+5)*([^45]|[^5]4)55+/. - Charles R Greathouse IV, Feb 11 2012

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000 (* First 500 terms from Vincenzo Librandi *)

Index entries for 6-automatic sequences.

MATHEMATICA

f[n_]:=Length[StringPosition[ToString[FromDigits[IntegerDigits[n, 6]]], "55", 1]]; Select[Table[n, {n, 2000}], f[#]>0&&f[#+1]==0&] (* Vincenzo Librandi, Feb 11 2012 *)

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 6], {5, 5}]>0, 1, 0], {n, 2000}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 13 2019 *)

CROSSREFS

Sequence in context: A043390 A031481 A044137 * A039382 A043205 A043985

Adjacent sequences:  A044515 A044516 A044517 * A044519 A044520 A044521

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified December 12 17:59 EST 2019. Contains 329960 sequences. (Running on oeis4.)