A334779 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly n local maxima.

1, 1, 2, 6, 88, 1480, 40272, 1476944, 71865728, 4454840448, 343059301120, 32120367997696, 3593423957597184, 473387964389590016, 72533147097036867584, 12789470502905585018880, 2571336187676016073080832, 584713932920281483718459392, 149314675071137196105777217536

Offset: 0

Author

Andrew Howroyd, May 13 2020

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..100

Crossrefs

Main diagonal of A334778.

Programs

PARI

\\ CircPeaksBySig defined in A334778.
a(n) = {if(n==0, 1, CircPeaksBySig(vector(n, i, 2), [n])[1])} \\ Andrew Howroyd, May 13 2020