A296905 Numbers whose base-20 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments.

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

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 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 * A345555 A345809 A279812

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