

A296762


Numbers n whose base20 digits d(m), d(m1), ..., 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
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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 A296762A296764 partition the natural numbers. See the guide at A296712.


LINKS

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


EXAMPLE

The base20 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



