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 A284436 #11 Jun 18 2025 00:48:57 %S A284436 1,2,6,2,18,12,24,24,792,240,1440,720,7488,10080,16992,40320,1013760, %T A284436 725760,979200,3628800,17902080,79833600,89510400,479001600, %U A284436 1988582400,11446272000,11931494400,108138240000,312309043200,1539772416000,2186163302400,19872992563200 %N A284436 The number of positive integer sequences of length n with no duplicate substrings (forward or backward) of length greater than 1, no self-adjacent terms, and a minimal product (= A282170(n)). %e A284436 For n = 4 the a(4) = 2 solutions are [1,3,2,1] and [1,2,3,1]. %Y A284436 Cf. A282170, A283557, A284433, A284434, A284435. %K A284436 nonn %O A284436 1,2 %A A284436 _Peter Kagey_, Mar 27 2017 %E A284436 Name edited and terms a(9) onward added by _Max Alekseyev_, Feb 06 2025