A044163 Numbers k such that string 3,4 occurs in the base 7 representation of k but not of k-1.

25, 74, 123, 172, 175, 221, 270, 319, 368, 417, 466, 515, 518, 564, 613, 662, 711, 760, 809, 858, 861, 907, 956, 1005, 1054, 1103, 1152, 1201, 1204, 1225, 1299, 1348, 1397, 1446, 1495, 1544, 1547, 1593, 1642, 1691, 1740, 1789, 1838, 1887, 1890, 1936, 1985, 2034, 2083

Offset

1,1

Links

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

Mathematica

A044163Q[k_] := StringContainsQ[IntegerString[k, 7], "34"] && StringFreeQ[IntegerString[k - 1, 7], "34"];
Select[Range[5000], A044163Q] (* Paolo Xausa, Sep 10 2025 *)

Crossrefs

Cf. A007093.

Sequence in context: A114553 A098439 A318643 * A044544 A045180 A270385

Adjacent sequences: A044160 A044161 A044162 * A044164 A044165 A044166

Keyword

nonn,base

Author

Clark Kimberling

Extensions

More terms from Paolo Xausa, Sep 10 2025

Status

approved