2014992domain: NAppears in sequencesa(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,6).at n=21A035039Number of complete rulers with length n.at n=23A103295Sum_{k=0..14} binomial(n,k).at n=21A220051E.g.f. A(x) satisfies A(x) = sqrt( 1 + 2*x*exp(x*A(x)) ).at n=9A380093