A296892 - OEIS

%I #7 Jan 21 2023 18:12:02

%S 170,171,172,173,174,175,176,177,178,179,180,181,339,340,341,342,343,

%T 344,345,346,347,348,349,350,353,354,355,356,357,358,359,360,361,362,

%U 363,508,509,510,511,512,513,514,515,516,517,518,519,522,523,524,525,526

%N Numbers whose base-13 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 A296891-A296894 partition the natural numbers. See the guides at A296712 and A296882.

%H Clark Kimberling, <a href="/A296892/b296892.txt">Table of n, a(n) for n = 1..10000</a>

%e The base-13 digits of 59672 are 2,1,2,1,2; here #(pits) = 2 and #(peaks) = 1, so 59672 is in the sequence.

%t z = 200; b = 13;

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

%t Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &]  (* A296891 *)

%t Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &]    (* A296892 *)

%t Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &]    (* A296893 *)

%Y Cf. A296882, A296712, A296891, A296893.

%K nonn,base,easy

%O 1,1

%A _Clark Kimberling_, Jan 12 2018