a(n) = Sum_{k=0..n} C(2k+2,k)*C(2k+2,n-k) ; equals row 2 of square array A137634 ; also equals the convolution of A137635 and the self-convolution of A073157.
A137637
a(n) = Sum_{k=0..n} C(2k+2,k)*C(2k+2,n-k) ; equals row 2 of square array A137634 ; also equals the convolution of A137635 and the self-convolution of A073157.
Terms
- a(0) =1a(1) =6a(2) =32a(3) =170a(4) =899a(5) =4764a(6) =25318a(7) =134964a(8) =721562a(9) =3868024a(10) =20785035a(11) =111931154a(12) =603938905a(13) =3264309644a(14) =17671408012a(15) =95800342628a(16) =520022296700
External references
- oeis: A137637