OFFSET
1,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..200
N. J. A. Sloane, Transforms
FORMULA
G.f. satisfies A^(-1)(x) = A(x)/x - 1.
G.f. satisfies: A(A(x)) = (1+x)*A(x) = g.f. of A107094. - Paul D. Hanna, May 12 2005
G.f. A(x) satisfies 0=f(x, A(x), A(A(x))) where f(a0,a1,a2) = a1 - a2 + a0*a1. - Michael Somos, May 21 2005
a(n) = T(n-1,1), n > 1, a(1) = 1, T(n,m) = (m/n) * Sum_{k=1..n-m} T(n-m,k) * (-1)^k * binomial(k+n-1, n-1), n > m, T(n,n) = 1. - Vladimir Kruchinin, May 06 2012
MATHEMATICA
Nest[InverseSeries[#] x + x &, x + O[x]^2, 50][[3]] (* Vladimir Reshetnikov, Aug 07 2019 *)
PROG
(PARI) {a(n)=local(A); if(n<1, 0, A=x+O(x^2); for(i=2, n, A=x*(1+serreverse(A))); polcoeff(A, n))} /* Michael Somos, May 21 2005 */
(Maxima) T(n, m):=if n=m then 1 else m/n*sum(T(n-m, k)*(-1)^k*binomial(k+n-1, n-1), k, 1, n-m); a(n):=if n=1 then 1 else T(n-1, 1); [Vladimir Kruchinin, May 06 2012]
CROSSREFS
KEYWORD
sign,eigen
AUTHOR
Christian G. Bower, Jan 03 2002
STATUS
approved