A191658 - OEIS

%I #6 Mar 30 2012 18:40:59

%S 1,2,3,6,3,45,4,3,9,45,315,120,9,9,45,135,315,14175,720,36,9,81,135,

%T 135,2025,315,945,14175,467775,5040,180,27,81,135,135,405,2025,945,

%U 945,14175,14175,42525,467775,42567525

%N Table, by rows, of denominators of alpha-coefficients in the symmetrized product of 2n Dirac matrices with two tensor indices.

%C The numerators are A191657. From table 1 by Izaurieta et al.

%H Fernando Izaurieta, Ricardo Ramírez, Eduardo Rodríguez, <a href="http://arxiv.org/abs/1106.1648">An efficient algorithm for the computation of the trace of the symmetrized product of an arbitrary number of Dirac matrices with two indices</a>, arXiv:1106.1648, June 08 2011.

%e The coefficients corresponding to each partition of 4 are:

%e 1 + 1 + 1 + 1 -> 1/24;

%e 2 + 1 + 1 -> -1/3;

%e 2 + 2 -> 2/9;

%e 3 + 1 -> 32/45;

%e 4 -> -272/315.

%Y Cf. A191657.

%K nonn,frac,tabf

%O 1,2

%A _Jonathan Vos Post_, Jun 10 2011