A296880 Numbers whose base-9 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments.

82, 83, 84, 85, 86, 87, 88, 89, 163, 164, 165, 166, 167, 168, 169, 170, 173, 174, 175, 176, 177, 178, 179, 244, 245, 246, 247, 248, 249, 250, 251, 254, 255, 256, 257, 258, 259, 260, 264, 265, 266, 267, 268, 269, 325, 326, 327, 328, 329, 330, 331, 332, 335

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 A296879-A296881 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-9 digits of 335 are 4,1,2; here #(pits) = 1 and #(peaks) = 0, so 335 is in the sequence.

Mathematica

z = 200; b = 9;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296879 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296880 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296881 *)

Crossrefs

Cf. A296882, A296712, A296879, A296881.

Sequence in context: A080535 A080536 A043632 * A077684 A044982 A181468

Adjacent sequences: A296877 A296878 A296879 * A296881 A296882 A296883

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 09 2018

Status

approved