A284433 The number of positive integer sequences of length n with no duplicate substrings (forward or backward) of length greater than 1, every number different from its neighbors, and a minimal sum (= A282167(n)).

1, 2, 6, 2, 18, 12, 24, 24, 1320, 240, 528, 720, 5664, 105888, 16992, 150048, 244800, 4266432, 4375296, 39598848, 50637312, 123310080, 202549248, 15925690368, 3765657600, 23454351360, 101739110400, 437749678080, 1572538613760, 11891771080704, 7862693068800, 185042766200832

Offset: 1

Author

Peter Kagey, Mar 27 2017

Keywords

• nonn

Examples

			For n = 4 the a(4) = 2 solutions are [1,3,2,1] and [1,2,3,1].
		

Crossrefs

Cf. A282167, A283558, A284431, A284432, A284436.

Extensions

Terms a(10) onward from Max Alekseyev, Feb 06 2025