A296866 Numbers whose base-4 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments.

24, 25, 28, 29, 30, 44, 45, 46, 88, 89, 92, 93, 94, 96, 100, 101, 108, 109, 110, 112, 116, 117, 120, 121, 122, 172, 173, 174, 176, 180, 181, 184, 185, 186, 260, 264, 265, 268, 269, 270, 344, 345, 348, 349, 350, 352, 356, 357, 364, 365, 366, 368, 372, 373

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 A296864-A296866 partition the natural numbers. See the guides at A296882 and A296712.

Links

Clark Kimberling, Table of n, a(n) for n = 1..9999

Example

The base-4 digits of 373 are 1,1,3,1,1; here #(pits) = 0 and #(peaks) = 2, so 373 is in the sequence.

Mathematica

z = 200; b = 4;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296864 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296865 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296866 *)

Crossrefs

Cf. A296882, A296712, A296864, A296865.

Sequence in context: A066024 A123608 A141587 * A241890 A027729 A008856

Adjacent sequences: A296863 A296864 A296865 * A296867 A296868 A296869

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 09 2018

Status

approved