OFFSET
0,1
FORMULA
a(n) ~ c * d^n * 2^(4*n^3/3 + 3*n^2) * exp(3*n^2/4) / (Pi^(n^2/2) * n^(3*n^2/2 + 3*n - alfa)), where
d = 1.755243767008515125359629831741161625491476427596217377285488419728083846...
alfa = 0.033913207252709141540468528132950860454628430850651543265936300855299...
c = 1.31959917222402005903928675604752142566298009509...
MATHEMATICA
Table[Product[CatalanNumber[i] + CatalanNumber[j], {i, 0, n}, {j, 0, n}], {n, 0, 7}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Mar 07 2019
STATUS
approved