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 A044200 Numbers n such that string 1,5 occurs in the base 8 representation of n but not of n-1. 1

%I #11 Jul 16 2017 11:06:11

%S 13,77,104,141,205,269,333,397,461,525,589,616,653,717,781,832,909,

%T 973,1037,1101,1128,1165,1229,1293,1357,1421,1485,1549,1613,1640,1677,

%U 1741,1805,1869,1933,1997,2061,2125,2152,2189,2253,2317,2381,2445,2509,2573

%N Numbers n such that string 1,5 occurs in the base 8 representation of n but not of n-1.

%t f[n_] := Length[StringPosition[ToString[FromDigits[IntegerDigits[n, 8]]], "15", 1]]; a = Select[Table[n, {n, 10000}], f[#] > 0 && f[# - 1] == 0 &] (* _Vladimir Joseph Stephan Orlovsky_, Jul 16 2011 *)

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,8],{1,5}]>0,1,0],{n,2600}],{0,1}][[All,2]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 16 2017 *)

%Y Cf. A044581.

%K nonn,base

%O 1,1

%A _Clark Kimberling_

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Last modified April 18 11:52 EDT 2024. Contains 371779 sequences. (Running on oeis4.)