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A296872 Numbers whose base-6 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments. 4
48, 49, 54, 55, 56, 60, 61, 62, 63, 66, 67, 68, 69, 70, 90, 91, 92, 96, 97, 98, 99, 102, 103, 104, 105, 106, 132, 133, 134, 135, 138, 139, 140, 141, 142, 174, 175, 176, 177, 178, 264, 265, 270, 271, 272, 276, 277, 278, 279, 282, 283, 284, 285, 286, 288, 294 (list; graph; refs; listen; history; text; internal format)
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 A296870-A296872 partition the natural numbers. See the guides at A296882 and A296712.
LINKS
EXAMPLE
The base-6 digits of 294 are 1,2,1,0; here #(pits) = 0 and #(peaks) = 1, so 294 is in the sequence.
MATHEMATICA
z = 200; b = 6;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296870 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296871 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296872 *)
CROSSREFS
Sequence in context: A121377 A327894 A332242 * A364702 A357429 A258694
KEYWORD
nonn,base,easy
AUTHOR
Clark Kimberling, Jan 09 2018
STATUS
approved

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Last modified April 21 19:32 EDT 2024. Contains 371885 sequences. (Running on oeis4.)