Triangular array T read by rows: T(n,0)=T(n,n)=1 for n >= 0; for n >= 2 and 1 <= k <= n-1, T(n,k) = T(n-1,k-1) + T(n-2,k-1) + T(n-1,k) if 1 <= k <= floor(n/2), else T(n,k) = T(n-1,k-1) + T(n-1,k).
A026780
Triangular array T read by rows: T(n,0)=T(n,n)=1 for n >= 0; for n >= 2 and 1 <= k <= n-1, T(n,k) = T(n-1,k-1) + T(n-2,k-1) + T(n-1,k) if 1 <= k <= floor(n/2), else T(n,k) = T(n-1,k-1) + T(n-1,k).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =1a(7) =5a(8) =4a(9) =1a(10) =1a(11) =7a(12) =12a(13) =5a(14) =1a(15) =1a(16) =9a(17) =24a(18) =17a(19) =6a(20) =1a(21) =1a(22) =11a(23) =40a(24) =53a(25) =23a(26) =7a(27) =1a(28) =1a(29) =13
External references
- oeis: A026780