This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A296880 #7 Jan 21 2023 19:48:22 %S A296880 82,83,84,85,86,87,88,89,163,164,165,166,167,168,169,170,173,174,175, %T A296880 176,177,178,179,244,245,246,247,248,249,250,251,254,255,256,257,258, %U A296880 259,260,264,265,266,267,268,269,325,326,327,328,329,330,331,332,335 %N A296880 Numbers whose base-9 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments. %C A296880 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 A296879-A296881 partition the natural numbers. See the guides at A296882 and A296712. %H A296880 Clark Kimberling, <a href="/A296880/b296880.txt">Table of n, a(n) for n = 1..10000</a> %e A296880 The base-9 digits of 335 are 4,1,2; here #(pits) = 1 and #(peaks) = 0, so 335 is in the sequence. %t A296880 z = 200; b = 9; %t A296880 d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]]; %t A296880 Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296879 *) %t A296880 Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296880 *) %t A296880 Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296881 *) %Y A296880 Cf. A296882, A296712, A296879, A296881. %K A296880 nonn,base,easy %O A296880 1,1 %A A296880 _Clark Kimberling_, Jan 09 2018