593445188743domain: NAppears in sequencesa(n) = (1 - (-7)^n)/8.at n=14A014989a(n) = 6*a(n-1) + 7*a(n-2), a(0) = 0, a(1) = 1.at n=15A015552a(n) = (n^(2*n+1) + 1) / (n+1).at n=7A179897