

A044482


Numbers k such that the string 4,4 occurs in the base5 representation of k but not of k+1.


1



24, 49, 74, 99, 124, 149, 174, 199, 224, 249, 274, 299, 324, 349, 374, 399, 424, 449, 474, 499, 524, 549, 574, 624, 649, 674, 699, 724, 749, 774, 799, 824, 849, 874, 899, 924, 949, 974, 999, 1024, 1049, 1074, 1099, 1124, 1149
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OFFSET

1,1


COMMENTS

a(n)+1 is divisible by 25 because the string 4,4 must be at the lower end of the base5 representation.  Joerg Arndt, Feb 13 2012


LINKS



EXAMPLE

49 is in the sequence because its base5 representation, 144, includes 44 as a substring, but the base5 representation of 50, 200, does not.
599 is not in the sequence because, although it is 4344 in base 5, 600 is 4400 in base 5.


MATHEMATICA

f[n_]:= Length[StringPosition[ToString[FromDigits[IntegerDigits[n, 5]]], "44", 1]]; Select[Table[n, {n, 2000}], f[#]>0&&f[#+1] == 0&] (* Vincenzo Librandi, Feb 12 2012 *)
SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 5], {4, 4}]>0, 1, 0], {n, 1200}], {1, 0}][[All, 1]] (* Harvey P. Dale, Aug 20 2021 *)


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



