OFFSET
1,2
COMMENTS
Also seventh column (m=6) of triangle A091543.
REFERENCES
P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem, Phys. Lett. A 309 (2003) 198-205.
FORMULA
a(n)= (2^(n-1))*product((3*j+1)*(6*j+1), j=0..n-1), n>=1. From eq.12 of the Blasiak et al. reference with r=8, s=2, k=1.
a(n)= (6^(2*n))*risefac(1/6, n)*risefac(1/3, n)/2, n>=1, with risefac(x, n) = Pochhammer(x, n).
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Feb 13 2004
STATUS
approved