|
|
A225688
|
|
E.g.f.: sec(x)^3+(sec(x)^2*tan(x)).
|
|
4
|
|
|
1, 1, 3, 8, 33, 136, 723, 3968, 25953, 176896, 1376643, 11184128, 101031873, 951878656, 9795436563, 104932671488, 1212135593793, 14544442556416, 186388033956483, 2475749026562048, 34859622790687713, 507711943253426176, 7791941518975112403, 123460740095103991808
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
Number of up-down min-max permutations of n elements.
|
|
LINKS
|
|
|
FORMULA
|
The e.g.f. can also be written as (1+sin(x))/cos(x)^3.
|
|
MATHEMATICA
|
Table[n!*SeriesCoefficient[(1+Sin[x])/Cos[x]^3, {x, 0, n}] , {n, 0, 20}] (* Vaclav Kotesovec, May 26 2013 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|