a(n) = Sum_{k=0..n} C(2k+1,k)*C(2k+1,n-k) ; equals row 1 of square array A137634; also equals the convolution of A137635 and A073157.
A137636
a(n) = Sum_{k=0..n} C(2k+1,k)*C(2k+1,n-k) ; equals row 1 of square array A137634; also equals the convolution of A137635 and A073157.
Terms
- a(0) =1a(1) =4a(2) =19a(3) =94a(4) =474a(5) =2431a(6) =12609a(7) =65972a(8) =347524a(9) =1840680a(10) =9792986a(11) =52296799a(12) =280163091a(13) =1504969409a(14) =8103433329a(15) =43722788132a(16) =236340999038
External references
- oeis: A137636