A296887 Numbers whose base-11 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments.

143, 144, 154, 155, 156, 165, 166, 167, 168, 176, 177, 178, 179, 180, 187, 188, 189, 190, 191, 192, 198, 199, 200, 201, 202, 203, 204, 209, 210, 211, 212, 213, 214, 215, 216, 220, 221, 222, 223, 224, 225, 226, 227, 228, 231, 232, 233, 234, 235, 236, 237, 238

Offset

1,1

Comments

A pit is an index i such that d(i-1) > d(i) < d(i+1); a peak is an index i such that d(i-1) < d(i) > d(i+1). The sequences A296885-A296887 partition the natural numbers. See the guides at A296712 and A296882.

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Example

The base-11 digits of 17447 are 1,2,1,2,1; here #(pits) = 1 and #(peaks) = 2, so 17447 is in the sequence.

Mathematica

z = 200; b = 11;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296885 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296886 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296887 *)

Crossrefs

Cf. A296882, A296712, A296885, A296886.

Sequence in context: A077494 A217142 A306090 * A293755 A160781 A217141

Adjacent sequences: A296884 A296885 A296886 * A296888 A296889 A296890

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 10 2018

Status

approved