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A044344 Numbers n such that string 1,2 occurs in the base 10 representation of n but not of n-1. 0

%I

%S 12,112,120,212,312,412,512,612,712,812,912,1012,1112,1120,1200,1312,

%T 1412,1512,1612,1712,1812,1912,2012,2112,2120,2212,2312,2412,2512,

%U 2612,2712,2812,2912,3012,3112,3120,3212,3312,3412

%N Numbers n such that string 1,2 occurs in the base 10 representation of n but not of n-1.

%t Select[Range[3500],MemberQ[Partition[IntegerDigits[#],2,1],{1,2}] && !MemberQ[ Partition[IntegerDigits[#-1],2,1],{1,2}]&] (* _Harvey P. Dale_, Jul 13 2014 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_

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Last modified September 26 20:34 EDT 2021. Contains 347672 sequences. (Running on oeis4.)