A297126 - OEIS

%I #11 Nov 13 2021 04:48:03

%S 1,2,4,8,9,12,13,14,17,18,22,24,25,26,27,28,29,31,35,36,37,38,39,40,

%T 41,42,43,44,45,49,51,52,53,54,55,56,58,62,63,66,67,68,71,72,73,74,75,

%U 76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,93,94,95

%N Numbers whose base-3 digits d(m), d(m-1),..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}.

%C These numbers comprise the complement of the set of numbers in the union of A297124 and A297125.

%H Robert Israel, <a href="/A297126/b297126.txt">Table of n, a(n) for n = 1..10000</a>

%e Base-3 digits of 95: 1,0,1,1,2, so that 95 is in the sequence.

%p filter:= proc(n) local L;

%p   L:= convert(n,base,3);

%p   member(0,L[2..-1]-L[1..-2])

%p end proc:

%p filter(1):= true: filter(2):= true:

%p select(filter, [$1..100]); # _Robert Israel_, Apr 12 2018

%t a[n_, b_] := Sign[Differences[IntegerDigits[n, b]]]; z = 300;

%t b = 3; t = Table[a[n, b], {n, 1, 10*z}];

%t u = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == 1 &]   (* A297124 *)

%t v = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == -1 &]  (* A297125 *)

%t Complement[Range[z], Union[u, v]]  (* A297126 *)

%Y Cf. A297124, A297125.

%K nonn,easy,base

%O 1,2

%A _Clark Kimberling_, Apr 10 2018

%E 3 removed by _Robert Israel_, Apr 12 2018