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A296886 Numbers whose base-11 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments. 4

%I #7 Jan 21 2023 20:28:44

%S 122,123,124,125,126,127,128,129,130,131,243,244,245,246,247,248,249,

%T 250,251,252,255,256,257,258,259,260,261,262,263,364,365,366,367,368,

%U 369,370,371,372,373,376,377,378,379,380,381,382,383,384,388,389,390,391

%N Numbers whose base-11 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments.

%C 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.

%H Clark Kimberling, <a href="/A296886/b296886.txt">Table of n, a(n) for n = 1..10000</a>

%e The base-11 digits of 30868 are 2,1,2,1,2; here #(pits) = 2 and #(peaks) = 1, so 30368 is in the sequence.

%t z = 200; b = 11;

%t d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]];

%t Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296885 *)

%t Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296886 *)

%t Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296887 *)

%Y Cf. A296882, A296712, A296885, A296887.

%K nonn,base,easy

%O 1,1

%A _Clark Kimberling_, Jan 10 2018

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Last modified June 17 07:12 EDT 2024. Contains 373433 sequences. (Running on oeis4.)