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A296886
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Numbers whose base-11 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments.
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4
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122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 255, 256, 257, 258, 259, 260, 261, 262, 263, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 376, 377, 378, 379, 380, 381, 382, 383, 384, 388, 389, 390, 391
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OFFSET
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1,1
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COMMENTS
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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 A296885-A296887 partition the natural numbers. See the guides at A296712 and A296882.
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LINKS
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EXAMPLE
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The base-11 digits of 30868 are 2,1,2,1,2; here #(pits) = 2 and #(peaks) = 1, so 30368 is in the sequence.
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MATHEMATICA
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z = 200; b = 11;
d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];
Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296885 *)
Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296886 *)
Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296887 *)
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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