1163969536domain: NAppears in sequencesExpansion of g.f. (1 + x - 2*x^2 - x^3)/(1/2 - 2*x^2 + x^4).at n=34A030435a(n) = (2 + sqrt(2))^n + (2 - sqrt(2))^n.at n=17A056236Number of meaningful differential operations of the k-th order on the space R^12.at n=30A129639