a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * binomial(3*k,k).
A383118
a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * binomial(3*k,k).
Terms
- a(0) =1a(1) =2a(2) =10a(3) =47a(4) =238a(5) =1232a(6) =6499a(7) =34715a(8) =187198a(9) =1016840a(10) =5555560a(11) =30497150a(12) =168073195a(13) =929348396a(14) =5153362231a(15) =28646281502a(16) =159579236014a(17) =890644144580
External references
- oeis: A383118