A044126 Numbers n such that string 4,0 occurs in the base 6 representation of n but not of n-1.

24, 60, 96, 132, 144, 168, 204, 240, 276, 312, 348, 360, 384, 420, 456, 492, 528, 564, 576, 600, 636, 672, 708, 744, 780, 792, 816, 852, 864, 924, 960, 996, 1008, 1032, 1068, 1104, 1140, 1176, 1212, 1224, 1248, 1284, 1320, 1356

Offset

1,1

Comments

All terms == 4*6^k (mod 6^(k+1)) for some k >= 1. However, not all numbers of this form are in the sequence, e.g., 888. - Robert Israel, Jun 13 2018

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:= 10^4: # for all terms <= N
filter:= proc(n) local L;
    L:= convert(n-1, base, 6);
    select(t -> L[t]=0 and L[t+1]=4, [$1..nops(L)-1])=[]
end proc:
S:= convert(`union`(seq({seq(i, i=4*6^k .. N, 6^(k+1))}, k=1..floor(log[6](N/4)))), list):
sort(select(filter, S)); # Robert Israel, Jun 13 2018

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 6], {4, 0}]>0, 1, 0], {n, 1500}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 17 2020 *)

Crossrefs

Sequence in context: A255968 A211325 A290303 * A044507 A101860 A163636

Adjacent sequences: A044123 A044124 A044125 * A044127 A044128 A044129

Keyword

nonn,base

Author

Clark Kimberling

Status

approved