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A296762 Numbers n whose base-20 digits d(m), d(m-1), ..., d(0) have #(rises) = #(falls); see Comments. 7
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 421 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A rise is an index i such that d(i) < d(i+1); a fall is an index i such that d(i) > d(i+1). The sequences A296762-A296764 partition the natural numbers. See the guide at A296712.

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..10000

EXAMPLE

The base-20 digits of 421 are 1,1,1; here #(rises) = 0 and #(falls) = 0, so that 421 is in the sequence.

MATHEMATICA

z = 200; b = 20; d[n_] := Sign[Differences[IntegerDigits[n, b]]];

Select[Range [z], Count[d[#], -1] == Count[d[#], 1] &] (* A296762 *)

Select[Range [z], Count[d[#], -1] < Count[d[#], 1] &]  (* A296763 *)

Select[Range [z], Count[d[#], -1] > Count[d[#], 1] &]  (* A296764 *)

CROSSREFS

Cf. A296763, A296764, A296712.

Sequence in context: A246097 A275776 A022465 * A247751 A059962 A057605

Adjacent sequences:  A296759 A296760 A296761 * A296763 A296764 A296765

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling, Jan 08 2018

STATUS

approved

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Last modified October 13 21:59 EDT 2019. Contains 327981 sequences. (Running on oeis4.)