A296884 Numbers whose base-10 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments.

120, 121, 130, 131, 132, 140, 141, 142, 143, 150, 151, 152, 153, 154, 160, 161, 162, 163, 164, 165, 170, 171, 172, 173, 174, 175, 176, 180, 181, 182, 183, 184, 185, 186, 187, 190, 191, 192, 193, 194, 195, 196, 197, 198, 230, 231, 232, 240, 241, 242, 243, 250

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 A296882-A296883 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-10 digits of 12121 are 1,2,1,2,1; here #(pits) = 1 and #(peaks) = 2, so 12121 is in the sequence.

Mathematica

z = 200; b = 10;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296882 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296883 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296884 *)

Crossrefs

Cf. A296882, A296712, A296882, A296883.

Sequence in context: A056456 A239535 A085218 * A117645 A157425 A030501

Adjacent sequences: A296881 A296882 A296883 * A296885 A296886 A296887

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 10 2018

Status

approved