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 A296883 #7 Jan 21 2023 20:28:30 %S A296883 101,102,103,104,105,106,107,108,109,201,202,203,204,205,206,207,208, %T A296883 209,212,213,214,215,216,217,218,219,301,302,303,304,305,306,307,308, %U A296883 309,312,313,314,315,316,317,318,319,323,324,325,326,327,328,329,401,402 %N A296883 Numbers whose base-10 digits d(m), d(m-1), ..., d(0) have #(pits) > #(peaks); see Comments. %C A296883 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 A296882-A296883 partition the natural numbers. See the guides at A296712 and A296882. %H A296883 Clark Kimberling, <a href="/A296883/b296883.txt">Table of n, a(n) for n = 1..10000</a> %e A296883 The base-10 digits of 21212 are 2,1,2,1,2; here #(pits) = 2 and #(peaks) = 1, so 21212 is in the sequence. %t A296883 z = 200; b = 10; %t A296883 d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]]; %t A296883 Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296882 *) %t A296883 Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296883 *) %t A296883 Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296884 *) %Y A296883 Cf. A296882, A296712, A296882, A296884. %K A296883 nonn,base,easy %O A296883 1,1 %A A296883 _Clark Kimberling_, Jan 10 2018