2684354559domain: NAppears in sequencesa(n) = 5*2^(n-1) - 1, n>0, with a(0)=1.at n=30A052549a(n) = Sum_{k=0..n} binomial(n+(-1)^k, k).at n=30A087940a(n) = 5*2^n - 1.at n=29A153894