A152498 1/3 of the number of permutations of 2 indistinguishable copies of 1..n with exactly 6 local maxima.

0, 0, 0, 0, 0, 76739, 42734373, 10478384089, 1717626773713, 222419564005134, 24781841211038024, 2496351029911357950, 234485896532293552830, 20959967704130971672341, 1807748255927878129526087, 151901517836714997413430591, 12521620421275657891377640951

Offset

1,6

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

Formula

a(n) = A334774(n,5)/3. - Andrew Howroyd, May 12 2020

Prog

(PARI) \\ PeaksBySig defined in A334774.
a(n)={PeaksBySig(vector(n, i, 2), [5])[1]/3}

Crossrefs

Cf. A334774.

Sequence in context: A357608 A046720 A258606 * A237747 A237746 A254171

Adjacent sequences: A152495 A152496 A152497 * A152499 A152500 A152501

Keyword

nonn

Author

R. H. Hardin, Dec 06 2008

Extensions

Terms a(11) and beyond from Andrew Howroyd, May 12 2020

Status

approved