

A229718


Number of arrays of length 2 that are sums of n consecutive elements of length 2+n1 permutations of 0..2+n2, and no two consecutive rises or falls in the latter permutation.


0



2, 4, 8, 18, 26, 40, 52, 70, 86, 108, 128, 154, 178, 208
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OFFSET

1,1


COMMENTS



LINKS



FORMULA

Empirical: a(n) = 2*a(n1)  2*a(n3) + a(n4) for n > 5.


EXAMPLE

Some solutions for n=4:
10 6 9 7 9 8 8 8 6 8 7 6 7 10 10 7
7 9 8 8 6 10 7 6 8 9 10 7 9 8 9 6


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



