a(n) = Sum_{k=0..floor(n/3)} (4*k+1) * binomial(3*n-5*k+1,n-3*k)/(3*n-5*k+1).
A390485
a(n) = Sum_{k=0..floor(n/3)} (4*k+1) * binomial(3*n-5*k+1,n-3*k)/(3*n-5*k+1).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =13a(4) =60a(5) =298a(6) =1559a(7) =8461a(8) =47202a(9) =269029a(10) =1559793a(11) =9170721a(12) =54549314a(13) =327673535a(14) =1984930805a(15) =12111852548a(16) =74377027931a(17) =459306563146
External references
- oeis: A390485