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A072350
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E.g.f. A(x) satisfies A(A(x)) = tan(x), where A(x) = Sum_{n>=1} a(n)*x^(2n-1)/(2n-1)!.
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1
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1, 1, 3, 17, 225, 3613, -42997, 8725357, 2116966081, -549193907111, -114757574954509, 117893333517545097, 14433599120070484321, -65568697910890921624715, 2968238619232726100394235, 86999609037195113208781248165
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| The inverse of this g.f. A(x) is the g.f. of A095885. - Paul D. Hanna (pauldhanna(AT)juno.com), Dec 09 2004
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LINKS
| Paul D. Hanna, Table of n, a(n) for n = 1..40
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FORMULA
| a(n)=(2*n-1)!*T(2*n-1,1), T(n,k)=if n=k then 1 else 1/2*(T059419(n,k)*k!/n!-sum(i=k+1..n-1, T(n,i)*T(i,k))). [From Vladimir Kruchinin, Nov 11 2011]
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EXAMPLE
| a(x) = x/1!+x^3/3!+3*x^5/5!+17*x^7/7!+225*x^9/9!+3613*x^11/11!-42997*x^13/13!+...
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PROG
| (PARI) {a(n)=local(A, B, F); F=tan(x+O(x^(2*n+1))); A=F; for(i=0, 2*n-1, B=serreverse(A); A=(A+subst(B, x, F))/2); if(n<1, 0, (2*n-1)!*polcoeff(A, 2*n-1, x))} (Hanna)
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CROSSREFS
| Cf. A048602, A048603, A052134, A052135.
Cf. A095885 (inverse).
Sequence in context: A009494 A075271 A194925 * A181032 A201107 A188803
Adjacent sequences: A072347 A072348 A072349 * A072351 A072352 A072353
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KEYWORD
| sign
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 17 2002
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EXTENSIONS
| More terms from Paul D. Hanna (pauldhanna(AT)juno.com), Dec 09 2004
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