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 A180070 #21 Mar 15 2024 12:48:49
%S A180070 1,1,2,6,12,44,116,374,1428,5960,26016,120570,590598,3065372,16566508,
%T A180070 92827128,542485764,3298228302,20696614200,133722820270,892046755174,
%U A180070 6136788856858,43308637312440,313079705562778,2322726645160856
%N A180070 Number of permutations of {1..n} with the sum of squared adjacent differences <= n*(n+1)/2.
%Y A180070 Cf. A180071.
%K A180070 nonn,hard
%O A180070 0,3
%A A180070 _R. H. Hardin_, Aug 09 2010
%E A180070 a(17)-a(18) from _Donovan Johnson_, Oct 11 2010
%E A180070 a(0)-a(1) from _Alois P. Heinz_, Sep 02 2020
%E A180070 a(19)-a(23) from _Martin Ehrenstein_, Nov 12 2023
%E A180070 a(24) from _Max Alekseyev_, Mar 15 2024