A296904 Numbers whose base-20 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments.

401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 801, 802, 803, 804, 805, 806, 807, 808, 809, 810, 811, 812, 813, 814, 815, 816, 817, 818, 819, 822, 823, 824, 825, 826, 827, 828, 829, 830, 831, 832, 833, 834, 835

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 328822 are 2,1,2,1,2; here #(pits) = 2 and #(peaks) = 1, so 328822 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, A296904, A296905.

Sequence in context: A268366 A013767 A013895 * A159890 A029705 A096991

Adjacent sequences: A296901 A296902 A296903 * A296905 A296906 A296907

Keyword

nonn,base,easy

Author

Clark Kimberling, Jan 12 2018

Status

approved