A334775 Number of permutations of 2 indistinguishable copies of 1..n with exactly n local maxima.

1, 3, 24, 339, 7392, 230217, 9689934, 529634931, 36463272996, 3086776079745, 315108659732034, 38170141911313467, 5412679282489599840, 888197438344278978537, 166988574370806672234630, 35659091146526471860555587, 8583030980293328579564829948, 2312892203852608268226402385617

Offset

1,2

Links

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

Prog

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

Crossrefs

Main diagonal of A334774.

Sequence in context: A370055 A371007 A144003 * A153389 A366000 A332975

Adjacent sequences: A334772 A334773 A334774 * A334776 A334777 A334778

Keyword

nonn

Author

Andrew Howroyd, May 11 2020

Status

approved