A284433 The number of positive integer sequences of length n with no duplicate substrings (forward or backward), every number different from its neighbors, and a minimal sum (i.e., the sum of the sequence is A282167(n)).

1, 2, 6, 2, 18, 12, 24, 24, 1320

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Example

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

Crossrefs

Cf. A282167.

Sequence in context: A372620 A236697 A235797 * A284436 A322312 A174857

Adjacent sequences: A284430 A284431 A284432 * A284434 A284435 A284436

Keyword

nonn,more

Author

Peter Kagey, Mar 27 2017

Status

approved