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A296862 Numbers whose base-3 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments. 4
10, 11, 19, 20, 23, 31, 32, 35, 37, 38, 58, 59, 62, 64, 65, 71, 73, 74, 77, 91, 92, 93, 94, 95, 98, 100, 101, 104, 105, 106, 107, 112, 113, 116, 118, 119, 154, 155, 158, 172, 173, 174, 175, 176, 179, 181, 182, 185, 186, 187, 188, 193, 194, 197, 199, 200, 208 (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 A296861-A296863 partition the natural numbers. See the guides at A296882 and A296712.
LINKS
EXAMPLE
The base-3 digits of 208 are 2, 1, 2, 0, 1; here #(pits) = 2 and #(peaks) = 1, so 208 is in the sequence.
MATHEMATICA
z = 200; b = 3;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296861 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296862 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296863 *)
CROSSREFS
Sequence in context: A214897 A037307 A341820 * A225079 A214790 A191221
KEYWORD
nonn,base,easy
AUTHOR
Clark Kimberling, Jan 09 2018
STATUS
approved

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Last modified July 19 16:24 EDT 2024. Contains 374410 sequences. (Running on oeis4.)