108005domain: NAppears in sequencesa(n) = a(n-1) + 3*a(n-2).at n=14A006138INVERT transform of A008805 (triangular numbers repeated).at n=13A178320a(n) = 4*n^3 + 5.at n=31A243762a(n) = Sum_{k=0..n} (2*k)^(n-k).at n=9A349970a(n) = Sum_{k=0..floor(n/2)} (n-2*k)^k.at n=18A352944