OFFSET
1,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..250
FORMULA
From Paul D. Hanna, Jan 31 2009: (Start)
G.f.: A(x) = 1/B(x) where A(x) = Sum_{n>=0} (-1)^n*a(n)*x^n/[n!*(n+1)!/2^n] and B(x) = Sum_{n>=0} x^n/[n!*(n+1)!/2^n].
G.f. satisfies: A(x) = 1/F(x*A(x)) and F(x) = 1/A(x*F(x)) where F(x) = Sum_{n>=0} A155926(n)*x^n/[n!*(n+1)!/2^n].
G.f. satisfies: A(x) = 1/G(x/A(x)) and G(x) = 1/A(x/G(x)) where G(x) = Sum_{n>=0} A155927(n)*x^n/[n!*(n+1)!/2^n]. (End)
a(n) ~ (-1)^(n+1) * c * n! * (n-1)! * d^n, where d = 4/BesselJZero[1, 1]^2 = 0.2724429913055159309179376055957891881897555639652..., and c = 9.11336321311226744479181866135367355200240221549667284076... = BesselJZero[1, 1]^2 / (4*BesselJ[2, BesselJZero[1, 1]]). - Vaclav Kotesovec, Mar 01 2014, updated Apr 01 2018
EXAMPLE
From Paul D. Hanna, Jan 31 2009: (Start)
G.f.: A(x) = 1 - x + 2*x^2/3 - 7*x^3/18 + 39*x^4/180 - 321*x^5/2700 +...
G.f.: A(x) = 1/B(x) where:
B(x) = 1 + x + x^2/3 + x^3/18 + x^4/180 + x^5/2700 +...+ x^n/[n!*(n+1)!/2^n] +... (End)
MATHEMATICA
Table[(-1)^((n-1)/2) * (CoefficientList[Series[x/BesselJ[1, 2*x], {x, 0, 40}], x])[[n]] * ((n+1)/2)! * ((n-1)/2)!, {n, 1, 41, 2}] (* Vaclav Kotesovec, Mar 01 2014 *)
PROG
(PARI) a(n)=if(n<1, 0, (matrix(n, n, m, j, binomial(m-1, j-1)*binomial(m, j-1)/j)^-1)[n, 1])
(PARI) {a(n)=local(B=sum(k=0, n, x^k/(k!*(k+1)!/2^k))+x*O(x^n)); polcoeff(1/B, n)*n!*(n+1)!/2^n} \\ Paul D. Hanna, Jan 31 2009
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Feb 02 2005
STATUS
approved