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A296704
Numbers whose base-7 digits d(m), d(m-1), ..., d(0) have #(rises) > #(falls); see Comments.
4
9, 10, 11, 12, 13, 17, 18, 19, 20, 25, 26, 27, 33, 34, 41, 58, 59, 60, 61, 62, 65, 66, 67, 68, 69, 73, 74, 75, 76, 81, 82, 83, 89, 90, 97, 115, 116, 117, 118, 122, 123, 124, 125, 130, 131, 132, 138, 139, 146, 172, 173, 174, 179, 180, 181, 187, 188, 195, 229
OFFSET
1,1
COMMENTS
A rise is an index i such that d(i) < d(i+1); a fall is an index i such that d(i) > d(i+1). The sequences A296703-A296705 partition the natural numbers. See the guide at A296712.
LINKS
EXAMPLE
The base-7 digits of 229 are 4,4,5; here #(rises) = 1 and #(falls) = 0, so 229 is in the sequence.
MATHEMATICA
z = 200; b = 7; d[n_] := Sign[Differences[IntegerDigits[n, b]]];
Select[Range [z], Count[d[#], -1] == Count[d[#], 1] &] (* A296703 *)
Select[Range [z], Count[d[#], -1] < Count[d[#], 1] &] (* A296704 *)
Select[Range [z], Count[d[#], -1] > Count[d[#], 1] &] (* A296705 *)
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Clark Kimberling, Jan 08 2018
STATUS
approved