A334777 Total number of local maxima in all permutations of 2 indistinguishable copies of 1..n.

1, 9, 195, 7140, 396900, 31185000, 3291888600, 449513064000, 77111922888000, 16235185926960000, 4116213602701200000, 1237059394731800640000, 434864246413372776000000, 176784623645708110032000000, 82297894534015170170160000000, 43496460979945066988294400000000

Offset: 1

Author

Andrew Howroyd, May 12 2020

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A000680, A334774, A334775, A334776.

Programs

PARI

\\ PeaksBySig defined in A334774.
a(n)={my(u=PeaksBySig(vector(n,i,2), [0..n-1])); sum(k=1, #u, k*u[k])}

Formula

a(n) = Sum_{k=1..n} k*A334774(n,k).

a(n) = A334776(n) + A000680(n).