A296908 Numbers whose base-60 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments.

3720, 3721, 3780, 3781, 3782, 3840, 3841, 3842, 3843, 3900, 3901, 3902, 3903, 3904, 3960, 3961, 3962, 3963, 3964, 3965, 4020, 4021, 4022, 4023, 4024, 4025, 4026, 4080, 4081, 4082, 4083, 4084, 4085, 4086, 4087, 4140, 4141, 4142, 4143, 4144, 4145, 4146, 4147

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 A296906..A296908 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-60 digits of 13395721 are 1,2,1,2,1; here #(pits) = 1 and #(peaks) = 2, so 13395721 is in the sequence.

Mathematica

z = 200; b = 60;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296906 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]   (* A296907 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]   (* A296908 *)

Crossrefs

Cf. A296882, A296712, A296906, A296907.

Sequence in context: A180396 A158917 A252421 * A237736 A289512 A260860

Adjacent sequences: A296905 A296906 A296907 * A296909 A296910 A296911

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 12 2018

Status

approved