A044387 - OEIS

A044387

Numbers n such that string 5,5 occurs in the base 10 representation of n but not of n-1.

55, 155, 255, 355, 455, 550, 655, 755, 855, 955, 1055, 1155, 1255, 1355, 1455, 1550, 1655, 1755, 1855, 1955, 2055, 2155, 2255, 2355, 2455, 2550, 2655, 2755, 2855, 2955, 3055, 3155, 3255, 3355, 3455, 3550, 3655, 3755, 3855

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OFFSET

1,1

LINKS

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

MATHEMATICA

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {5, 5}]>0, 1, 0], {n, 4000}], {0, 1}][[All, 2]] (* Harvey P. Dale, Aug 13 2021 *)

CROSSREFS

Sequence in context: A072429 A046438 A043510 * A044768 A352268 A276050

Adjacent sequences: A044384 A044385 A044386 * A044388 A044389 A044390

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved