read EKHAD:

H:=proc(n,m,a1,a2,a3):
rf(-n-m,k)*rf(x+m+1+a1,k)*rf(x+m-n+a2,k)*rf(x-z+1/2,k)*rf(z+1,k)/
k!/rf(x-n+1,2*k)/rf(2*z+m-n+1+a3,k)/rf(a1+a2-a3+1+2*x-2*z,k)*4^k:
end:

 
Pn1:=proc(n)
local gu:
rf(1/2,n)*rf(2*z-x,2*n)/rf(x+1,n)/rf(1+x-z,n)/rf(z+n+1/2,n):
end:
 
Pn:=proc(n)
local gu:
rf(1/2,n)*rf(2*z-x-n,2*n)/rf(x-n+1,n)/rf(1+x-z,n)/rf(z+1/2,n):
end:
 
print(`Identity 4.2 of Geroge Andrews's papar Pfaff Method I`):

H1:=H(n,n+1,0,0,0):
 
zeilpap(H1,k,n):
print(`This took`):
print(time()):
print(`Seconds of CPU time`):
quit: