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A156213 G.f.: A(x) = exp( Sum_{n>=1} 2^(n^2)*C(2*n-1,n)*x^n/n ), a power series in x with integer coefficients. 1
1, 2, 26, 1756, 577190, 846763548, 5293107304932, 138013765804872888, 14838375909837963204230, 6530915607537754235471687212, 11710315776946229385945240614099084 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Compare to g.f. of Catalan sequence: exp( Sum_{n>=1} C(2*n-1,n)*x^n/n ), where C(2*n-1,n) = A001700(n-1).
LINKS
EXAMPLE
G.f.: A(x) = 1 + 2*x + 26*x^2 + 1756*x^3 + 577190*x^4 + 846763548*x^5 +...
log(A(x)) = 2*x + 2^4*3*x^2/2 + 2^9*10*x^3/3 + 2^16*35*x^4/4 + 2^25*126*x^5/5 +...
PROG
(PARI) {a(n)=polcoeff(exp(sum(m=1, n, 2^(m^2)*binomial(2*m-1, m)*x^m/m)+x*O(x^n)), n)}
CROSSREFS
Sequence in context: A158120 A209916 A337578 * A159318 A318132 A134795
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Feb 06 2009
STATUS
approved

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Last modified March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)