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A296880 Numbers n whose base-9 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments. 4
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 (list; graph; refs; listen; history; text; internal format)
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 that 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

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Last modified September 17 10:15 EDT 2021. Contains 347478 sequences. (Running on oeis4.)