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A012023
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E.g.f.: cos(sin(arctan(x))) (even powers).
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0
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1, -1, 13, -421, 25369, -2449801, 346065061, -67243537453, 17192488230961, -5593309059948049, 2255588021494237501, -1103994926592923677621, 644587811150505183179593, -442516027690815793746696601
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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FORMULA
| a(n)=(2*n)!*(-1)^n*sum(j=0..n, binomial(n-1,n-j)/(2*j)!). [From Vladimir Kruchinin, May 19 2011]
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EXAMPLE
| cos(sin(arctan(x)))=1-1/2!*x^2+13/4!*x^4-421/6!*x^6+25369/8!*x^8-+...
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PROG
| (Maxima)
a(n):=(2*n)!*(-1)^n*sum(binomial(n-1, n-j)/(2*j)!, j, 0, n); [From Vladimir Kruchinin, May 19 2011]
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CROSSREFS
| Sequence in context: A087872 A098890 * A081442 A100872 A012045 A012109
Adjacent sequences: A012020 A012021 A012022 * A012024 A012025 A012026
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KEYWORD
| sign
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AUTHOR
| Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)
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