A296764 Numbers whose base-20 digits d(m), d(m-1), ..., d(0) have #(rises) < #(falls); see Comments.

20, 40, 41, 60, 61, 62, 80, 81, 82, 83, 100, 101, 102, 103, 104, 120, 121, 122, 123, 124, 125, 140, 141, 142, 143, 144, 145, 146, 160, 161, 162, 163, 164, 165, 166, 167, 180, 181, 182, 183, 184, 185, 186, 187, 188, 200, 201, 202, 203, 204, 205, 206, 207, 208

Offset

1,1

Comments

A rise is an index i such that d(i) < d(i+1); a fall is an index i such that d(i) > d(i+1). The sequences A296762-A296764 partition the natural numbers. See the guide at A296712.

Links

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

Example

The base-20 digits of 208 are 10,8; here #(rises) = 0 and #(falls) = 2, so 208 is in the sequence.

Mathematica

z = 200; b = 20; d[n_] := Sign[Differences[IntegerDigits[n, b]]];
Select[Range [z], Count[d[#], -1] == Count[d[#], 1] &] (* A296762 *)
Select[Range [z], Count[d[#], -1] < Count[d[#], 1] &]  (* A296763 *)
Select[Range [z], Count[d[#], -1] > Count[d[#], 1] &]  (* A296764 *)

Crossrefs

Cf. A296762, A296763, A296712.

Sequence in context: A040380 A154044 A235289 * A046794 A104153 A049057

Adjacent sequences: A296761 A296762 A296763 * A296765 A296766 A296767

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 08 2018

Status

approved