Algorithm B1 Computation of $p(j,k)$

Require: coefficients $a_1,a_2,a_3,a_4$, integer N

Define an array p of size $N\times 2N-1$

for $k=0:2(N-1)$ do

$p(0,k)=1$

end for

for $k=1:2(N-1)$ do

for $j=1:2(N-1)$ do

$p(j,k)=p(j,k-1)+a_{1}p(j-1,k-1)+a_{2}p(j-2,k-1)+a_{3}p(j-3,k-1)+a_{4}p(j-4,k-1)$

▹ With $p(j,k)=0$ as soon as $j<0$ or $k\le 0$

end for

end for

return p