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 A044519 Numbers n such that string 0,0 occurs in the base 7 representation of n but not of n+1. 1

%I #13 Jan 27 2021 13:54:35

%S 49,98,147,196,245,294,349,392,441,490,539,588,637,692,735,784,833,

%T 882,931,980,1035,1078,1127,1176,1225,1274,1323,1378,1421,1470,1519,

%U 1568,1617,1666,1721,1764,1813,1862,1911,1960,2009,2064,2107,2156,2205,2254,2303

%N Numbers n such that string 0,0 occurs in the base 7 representation of n but not of n+1.

%H Harvey P. Dale, <a href="/A044519/b044519.txt">Table of n, a(n) for n = 1..1000</a>

%t f[n_] := Length[StringPosition[ToString[FromDigits[IntegerDigits[n, 7]]], "00", 1]]; Select[Table[n, {n, 10000}], f[#] > 0 && f[# + 1] == 0 &] (* _Vladimir Joseph Stephan Orlovsky_, Jul 23 2011 *)

%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,7],{0,0}]>0,1,0],{n,2500}],{1,0}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jan 27 2021 *)

%Y Cf. A044138.

%K nonn,base

%O 1,1

%A _Clark Kimberling_

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Last modified August 11 17:54 EDT 2024. Contains 375073 sequences. (Running on oeis4.)