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A296905 Numbers n whose base-20 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments. 4
440, 441, 460, 461, 462, 480, 481, 482, 483, 500, 501, 502, 503, 504, 520, 521, 522, 523, 524, 525, 540, 541, 542, 543, 544, 545, 546, 560, 561, 562, 563, 564, 565, 566, 567, 580, 581, 582, 583, 584, 585, 586, 587, 588, 600, 601, 602, 603, 604, 605, 606, 607 (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 A296903..A296905 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-20 digits of 176441 are 1,2,1,2,1; here #(pits) = 1 and #(peaks) = 2, so that 176441 is in the sequence.

MATHEMATICA

z = 200; b = 20;

d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];

Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296903 *)

Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296904 *)

Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296905 *)

CROSSREFS

Cf. A296882, A296712, A296903, A296904.

Sequence in context: A177489 A210205 A092048 * A279812 A279950 A072604

Adjacent sequences:  A296902 A296903 A296904 * A296906 A296907 A296908

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling, Jan 12 2018

EXTENSIONS

b-file replaced by Clark Kimberling, Feb 27 2018

STATUS

approved

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Last modified September 27 08:12 EDT 2020. Contains 337380 sequences. (Running on oeis4.)