A296868 Numbers whose base-5 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments.

26, 27, 28, 29, 51, 52, 53, 54, 57, 58, 59, 76, 77, 78, 79, 82, 83, 84, 88, 89, 101, 102, 103, 104, 107, 108, 109, 113, 114, 119, 131, 132, 133, 134, 137, 138, 139, 143, 144, 149, 151, 152, 153, 154, 256, 257, 258, 259, 262, 263, 264, 268, 269, 274, 276, 277

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 A296867-A296869 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-5 digits of 277 are 2,1,0,2; here #(pits) = 1 and #(peaks) = 0, so 277 is in the sequence.

Mathematica

z = 200; b = 5;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296867 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296868 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296869 *)

Crossrefs

Cf. A296882, A296712, A296867, A296869.

Sequence in context: A094835 A034067 A043603 * A277602 A022396 A042362

Adjacent sequences: A296865 A296866 A296867 * A296869 A296870 A296871

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 09 2018

Status

approved