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Search: id:A136632
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| 1, 2, 16, 520, 66560, 33882144, 69055086592, 564152735105152, 18462508115518554112, 2418626436468567646929408, 1267795674038260517176495570944, 2658560573512321601282555747644737536
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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Contribution from Paul D. Hanna (pauldhanna(AT)juno.com), Nov 25 2009: (Start)
E.g.f.: Sum_{n>=0} sinh(2^n*x)^n/n!.
a(n) = [x^n/n! ] exp(2^n*sinh(x)).
(End)
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EXAMPLE
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Contribution from Paul D. Hanna (pauldhanna(AT)juno.com), Nov 25 2009: (Start)
E.g.f.: A(x) = 1 + 2*x + 16*x^2/2! + 520*x^3/3! + 66560*x^4/4! +...
A(x) = 1 + sinh(2*x) + sinh(4*x)^2/2! + sinh(8*x)^3/3! + sinh(16*x)^4/4! +...+ sinh(2^n*x)^n/n! +...
a(n) = coefficient of x^n/n! in G(x)^(2^n) where G(x) = exp(sinh(x)):
G(x) = 1 + x + x^2/2! + 2*x^3/3! + 5*x^4/4! + 12*x^5/5! + 37*x^6/6! +...+ A003724(n)*x^n/n! +... (End)
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PROGRAM
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(PARI) {a(n)=sum(k=0, n, 2^(n*k)*polcoeff(x^k/prod(j=0, k\2, 1-(2*j+k-2*(k\2))^2*x^2 +x*O(x^n)), n))}
Contribution from Paul D. Hanna (pauldhanna(AT)juno.com), Nov 25 2009: (Start)
(PARI) {a(n)=n!*polcoeff(sum(k=0, n, sinh(2^k*x +x*O(x^n))^k/k!), n)}
(PARI) {a(n)=n!*polcoeff(exp(2^n*sinh(x +x*O(x^n))), n)} (End)
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CROSSREFS
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Cf. A136630, A003724 (row sums of A136630).
Sequence in context: A063391 A002416 A013028 this_sequence A012919 A012914 A013087
Adjacent sequences: A136629 A136630 A136631 this_sequence A136633 A136634 A136635
Cf. A003724 (exp(sinh x)). [From Paul D. Hanna (pauldhanna(AT)juno.com), Nov 25 2009]
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KEYWORD
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nonn,new
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jan 14 2008
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