-343436893650domain: ZAppears in sequencesE.g.f. A(x) satisfies [x^k] A(x)^(n*(n+1)/2+1) = 0 for k = n*(n-1)/2+2 through k = n*(n+1)/2+1 for n >= 1, with a(0) = a(1) = 1.at n=12A377105