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A296878 Numbers whose base-8 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments. 4
80, 81, 88, 89, 90, 96, 97, 98, 99, 104, 105, 106, 107, 108, 112, 113, 114, 115, 116, 117, 120, 121, 122, 123, 124, 125, 126, 152, 153, 154, 160, 161, 162, 163, 168, 169, 170, 171, 172, 176, 177, 178, 179, 180, 181, 184, 185, 186, 187, 188, 189, 190, 224 (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 A296876-A296878 partition the natural numbers. See the guides at A296882 and A296712.
LINKS
EXAMPLE
The base-8 digits of 224 are 3,4,0; here #(pits) = 0 and #(peaks) = 1, so 224 is in the sequence.
MATHEMATICA
z = 200; b = 8;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296876 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296877 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296878 *)
CROSSREFS
Sequence in context: A220088 A126783 A255477 * A114836 A294740 A069086
KEYWORD
nonn,base,easy
AUTHOR
Clark Kimberling, Jan 09 2018
STATUS
approved

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Last modified June 20 21:53 EDT 2024. Contains 373532 sequences. (Running on oeis4.)