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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
12, 112, 120, 212, 312, 412, 512, 612, 712, 812, 912, 1012, 1112, 1120, 1200, 1312, 1412, 1512, 1612, 1712, 1812, 1912, 2012, 2112, 2120, 2212, 2312, 2412, 2512, 2612, 2712, 2812, 2912, 3012, 3112, 3120, 3212, 3312, 3412 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..39.

MATHEMATICA

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

CROSSREFS

Sequence in context: A077754 A199357 A293872 * A130838 A225189 A044725

Adjacent sequences:  A044341 A044342 A044343 * A044345 A044346 A044347

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified July 31 22:39 EDT 2021. Contains 346377 sequences. (Running on oeis4.)