A044149 - OEIS

A044149

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

11, 60, 77, 109, 158, 207, 256, 305, 354, 403, 420, 452, 501, 539, 599, 648, 697, 746, 763, 795, 844, 893, 942, 991, 1040, 1089, 1106, 1138, 1187, 1236, 1285, 1334, 1383, 1432, 1449, 1481, 1530, 1579, 1628, 1677, 1726, 1775, 1792, 1824, 1873, 1922, 1971, 2020, 2069, 2118

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OFFSET

1,1

LINKS

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

MATHEMATICA

A044149Q[k_] := StringContainsQ[IntegerString[k, 7], "14"] && StringFreeQ[IntegerString[k - 1, 7], "14"];

Select[Range[5000], A044149Q] (* Paolo Xausa, Sep 10 2025 *)

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 7], {1, 4}]>0, 1, 0], {n, 2500}], {0, 1}][[;; , 2]] (* Harvey P. Dale, May 05 2026 *)

CROSSREFS

Cf. A007093.

Sequence in context: A077036 A076604 A076676 * A044530 A050483 A066999