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 A284434 #15 Feb 06 2025 21:33:43 %S A284434 1,2,1,6,2,24,6,120,24,84,192,336,360,1680,2160,10080,26640,70560, %T A284434 80640,564480,645120,13789440,10644480,78382080,43545600,783820800, %U A284434 435456000,2264371200,12454041600,22643712000,117747302400,466460467200,367873228800,2391175987200,4414478745600 %N A284434 The number of positive integer sequences of length n with no duplicate substrings of length greater than 1, every number different from its neighbors, and a minimal product (= A282169(n)). %e A284434 For n = 7 the a(7) = 6 solutions are: %e A284434 [1,4,1,3,1,2,1], %e A284434 [1,3,1,4,1,2,1], %e A284434 [1,4,1,2,1,3,1], %e A284434 [1,2,1,4,1,3,1], %e A284434 [1,3,1,2,1,4,1], and %e A284434 [1,2,1,3,1,4,1]. %Y A284434 Cf. A282169, A283557, A284431, A284435, A284436. %K A284434 nonn %O A284434 1,2 %A A284434 _Peter Kagey_, Mar 27 2017 %E A284434 Terms a(8) onward from _Max Alekseyev_, Feb 05 2025