A296878 Numbers whose base-8 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments.

80, 81, 88, 89, 90, 96, 97, 98, 99, 104, 105, 106, 107, 108, 112, 113, 114, 115, 116, 117, 120, 121, 122, 123, 124, 125, 126, 152, 153, 154, 160, 161, 162, 163, 168, 169, 170, 171, 172, 176, 177, 178, 179, 180, 181, 184, 185, 186, 187, 188, 189, 190, 224

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 A296876-A296878 partition the natural numbers. See the guides at A296882 and A296712.

Links

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

Example

The base-8 digits of 224 are 3,4,0; here #(pits) = 0 and #(peaks) = 1, so 224 is in the sequence.

Mathematica

z = 200; b = 8;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296876 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296877 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296878 *)

Crossrefs

Cf. A296882, A296712, A296876, A296877.

Sequence in context: A220088 A126783 A255477 * A114836 A294740 A069086

Adjacent sequences: A296875 A296876 A296877 * A296879 A296880 A296881

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 09 2018

Status

approved