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A242154 revision #7

A242154

Number of ascent sequences of length n with exactly one flat step.

1, 2, 6, 20, 80, 366, 1897, 10976, 70155, 490930, 3733246, 30655152, 270334766, 2548153230, 25566585450, 272052199520, 3060191748695, 36282298766760, 452220051658265, 5911274512571280, 80862988937379390, 1155309461910323610, 17208404375488550100

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,2

LINKS

Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 2..140

FORMULA

a(n) ~ 2*sqrt(3)/(exp(Pi^2/12)*sqrt(Pi)) * (6/Pi^2)^n * n! * sqrt(n). - Vaclav Kotesovec, Aug 27 2014

CROSSREFS

Column k=1 of A242153.

Sequence in context: A144168 A177482 A300011 * A108124 A186365 A245373

Adjacent sequences: A242151 A242152 A242153 * A242155 A242156 A242157

KEYWORD

nonn

AUTHOR

Joerg Arndt and Alois P. Heinz, May 05 2014

STATUS

approved