A107720 Column 0 of triangle A107719.
1, 1, 5, 43, 509, 7579, 135341, 2813851, 66733853, 1778159275, 52604224205, 1711276244731, 60729274013309, 2335153500391627, 96727188777453869, 4294441686826824091, 203456100846249179357, 10245810557884742785387
Offset: 0
Keywords
Programs
-
PARI
{a(n)=local(E,L,M=matrix(n+1,n+1,m,j,if(m>=j,if(m==j,1,if(m==j+1,-3*j, -polcoeff(1-(1+sum(c=1,m-j,prod(i=0,c-1,3*i+1)*x^c)+x*O(x^(m-j)))^-1,m-j);))))^-1); L=matrix(#M,#M,r,c,if(r>=c,sum(i=1,#M,(-1)^(i-1)*(M-M^0)^i/i)[r,c])); E=matrix(#L,#L,r,c,if(r>=c,sum(i=0,#L,L^i/3^i/i!)[r,c])); if(n<0,0,E[n+1,1])}