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A080832
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Expansion of the exponential series Exp[x] Sec[ Exp[x] - 1 ]^2.
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1
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1, 1, 3, 13, 67, 421, 3115, 26349, 250867, 2655541, 30929019, 393019837, 5410699075, 80221867909, 1274393162827, 21594697199757, 388796268801427, 7411769447027413, 149143210226032923, 3159088788867736669
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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FORMULA
| E.G.F. Exp[x] Sec[ Exp[x] - 1 ]^2
The sequence 0, 1, 1, 3, ... has e.g.f. tan(exp(x)-1). It has general term sum{k=0..n, S2(n, k)A009006(k)} for n>1 (S2(n, k) Stirling numbers of second kind). - Paul Barry (pbarry(AT)wit.ie), Apr 20 2005
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CROSSREFS
| Sequence in context: A107592 A028418 A180191 * A194019 A020017 A060014
Adjacent sequences: A080829 A080830 A080831 * A080833 A080834 A080835
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KEYWORD
| easy,nonn
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AUTHOR
| Emanuele Munarini (munarini(AT)mate.polimi.it), Mar 28 2003
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