A044143 Numbers k such that string 0,5 occurs in the base 7 representation of k but not of k-1.

54, 103, 152, 201, 250, 299, 348, 378, 397, 446, 495, 544, 593, 642, 691, 721, 740, 789, 838, 887, 936, 985, 1034, 1064, 1083, 1132, 1181, 1230, 1279, 1328, 1377, 1407, 1426, 1475, 1524, 1573, 1622, 1671, 1720, 1750, 1769, 1818, 1867, 1916, 1965, 2014, 2063, 2093, 2112

Offset

1,1

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Mathematica

A044143Q[k_] := StringContainsQ[IntegerString[k, 7], "05"] && StringFreeQ[IntegerString[k - 1, 7], "05"];
Select[Range[5000], A044143Q] (* Paolo Xausa, Sep 10 2025 *)

Crossrefs

Cf. A007093.

Sequence in context: A259717 A118150 A039779 * A044524 A095962 A229358

Adjacent sequences: A044140 A044141 A044142 * A044144 A044145 A044146

Keyword

nonn,base

Author

Clark Kimberling

Extensions

More terms from Paolo Xausa, Sep 10 2025

Status

approved