OFFSET
0,5
COMMENTS
a(n) is the determinant of the n X n tridiagonal matrix M with m(i,j) = min(i,j).
LINKS
R. A. Usmani, Inversion of Jacobi's Tridiagonal Matrix, Computers Math. Applic. 27 (8), (1994), 59-66.
FORMULA
E.g.f.: e^(atan((-1+2z)/sqrt(3))/sqrt(3)) * e^(Pi/(6*sqrt(3))) / sqrt(1 - z + z^2).
MATHEMATICA
c=CoefficientList[Series[Exp[ArcTan[(-1+2z)/Sqrt[3]]/Sqrt[3]]*Exp[Pi/(6*Sqrt[3])]/Sqrt[1 - z + z^2], {z, 0, 25}], z]; For[n=0, n<26, n++; Print[c[[n]]*(n-1)! ]]
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Feb 06 2003
STATUS
approved