2391430020domain: NAppears in sequencesSum_{i=0..n} Sum_{j=0..i} a(j) * a(i-j) = (-7)^n.at n=12A085456a(n) = 4*Sum_{i=0..n-1} C(2*i+1, i)*C(n-1, n-1-i)*(-1)^(n-1-i)*2^i for n > 0, a(0) = 1.at n=12A085458