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 A379880 #20 Jan 20 2025 17:52:09 %S A379880 3,2,3,2,3,4,4,1,4,6,1,4,6,1,3,2,3,1,8,4,9,1,4,3,9,1,9,11,1,9,11,1,3, %T A379880 2,3,2,3,1,13,1,1,4,3,14,1,4,8,14,1,1,2,3,8,16,1,1,2,3,8,16,1,16,18,1, %U A379880 16,18,1,3,2,3,2,3,2,3,19,1,4,15,21,1,4,15 %N A379880 a(n) is the length of the n-th maximum run of consecutive terms of A377091 in arithmetic progression with common difference 1 or -1. %C A379880 Since the terms in A377091 are required to be distinct, in this arithmetic progression the differences are either all +1 or all -1. - _N. J. A. Sloane_, Jan 20 2025 %H A379880 Rémy Sigrist, <a href="/A379880/b379880.txt">Table of n, a(n) for n = 1..10000</a> %H A379880 Rémy Sigrist, <a href="/A379880/a379880.txt">C++ program</a> %e A379880 A377091 begins: %e A379880 0, 1, 2, -2, -1, 3, 4, 5, -4, -3, 6, 7, 8, -8, -7, -6, -5, -9. %e A379880 So the present sequence begins: %e A379880 3, 2, 3, 2, 3, 4. %t A379880 (* A377091list is defined at A377091 *) %t A379880 Map[Length, Most[Split[A377091list[500], Abs[#2 - #1] == 1 &]]] (* _Paolo Xausa_, Jan 20 2025 *) %o A379880 (C++) // See Links section. %Y A379880 Cf. A377091, A380223 (positions of ones). %K A379880 nonn %O A379880 1,1 %A A379880 _Rémy Sigrist_, Jan 05 2025