67459domain: NAppears in sequencesNumber of length n+2 0..2 arrays with the sum of second differences squared multiplied by some arrangement of +-1 equal to zero.at n=8A250314G.f. A(x) satisfies: A(x) = x * exp( A(x)^2/x + A(-x^2)^2/(2*x^2) + A(x^3)^2/(3*x^3) + A(-x^4)^2/(4*x^4) + ... ).at n=9A363294