a(n) = Sum_{k=0..floor((n-1)/2)} T(n,k) * T(n,k+1), with T given by A008315.
A027302
a(n) = Sum_{k=0..floor((n-1)/2)} T(n,k) * T(n,k+1), with T given by A008315.
Terms
- a(0) =1a(1) =2a(2) =9a(3) =24a(4) =95a(5) =286a(6) =1099a(7) =3536a(8) =13479a(9) =45220a(10) =172150a(11) =594320a(12) =2265003a(13) =7983990a(14) =30487175a(15) =109174560a(16) =417812417a(17) =1514797020a(18) =5810065898a(19) =21275014800a(20) =81775140083a(21) =301892460012
External references
- oeis: A027302