A297126 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}.

1, 2, 4, 8, 9, 12, 13, 14, 17, 18, 22, 24, 25, 26, 27, 28, 29, 31, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 49, 51, 52, 53, 54, 55, 56, 58, 62, 63, 66, 67, 68, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 93, 94, 95

Offset

1,2

Comments

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

Links

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

Example

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

Maple

filter:= proc(n) local L;
  L:= convert(n, base, 3);
  member(0, L[2..-1]-L[1..-2])
end proc:
filter(1):= true: filter(2):= true:
select(filter, [$1..100]); # Robert Israel, Apr 12 2018

Mathematica

a[n_, b_] := Sign[Differences[IntegerDigits[n, b]]]; z = 300;
b = 3; t = Table[a[n, b], {n, 1, 10*z}];
u = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == 1 &]   (* A297124 *)
v = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == -1 &]  (* A297125 *)
Complement[Range[z], Union[u, v]]  (* A297126 *)

Crossrefs

Cf. A297124, A297125.

Sequence in context: A338047 A243186 A326673 * A044814 A342009 A304451

Adjacent sequences: A297123 A297124 A297125 * A297127 A297128 A297129

Keyword

nonn,easy,base

Author

Clark Kimberling, Apr 10 2018

Extensions

3 removed by Robert Israel, Apr 12 2018

Status

approved