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A225689
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E.g.f.: sec(x)^2*tan(x)+sec(x)*tan(x)^2.
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6
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0, 1, 2, 8, 28, 136, 662, 3968, 24568, 176896, 1326122, 11184128, 98329108, 951878656, 9596075582, 104932671488, 1192744081648, 14544442556416, 183983154281042, 2475749026562048, 34489251602450188, 507711943253426176, 7722592644581974502, 123460740095103991808, 2035778987564783402728
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OFFSET
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0,3
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COMMENTS
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Number of up-down max-min permutations of n elements.
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LINKS
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FORMULA
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The e.g.f. can also be written as sin(x)*(1+sin(x))/cos(x)^3.
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MATHEMATICA
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Table[n!*SeriesCoefficient[Sin[x]*(1+Sin[x])/Cos[x]^3, {x, 0, n}] , {n, 0, 20}] (* Vaclav Kotesovec, May 26 2013 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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