Triangular array T(n,k): start with T(n,0)=T(n,n)=1 for n >= 0; recursively, draw vertical lines through T(n-1,k-1) if present and T(n-1,k) if present; then T(n,k) is the sum of T(i,j) that lie on or between the lines and not below T(n,k).
A054120
Triangular array T(n,k): start with T(n,0)=T(n,n)=1 for n >= 0; recursively, draw vertical lines through T(n-1,k-1) if present and T(n-1,k) if present; then T(n,k) is the sum of T(i,j) that lie on or between the lines and not below T(n,k).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =1a(7) =6a(8) =6a(9) =1a(10) =1a(11) =9a(12) =18a(13) =9a(14) =1a(15) =1a(16) =12a(17) =39a(18) =39a(19) =12a(20) =1a(21) =1a(22) =15a(23) =69a(24) =114a(25) =69a(26) =15a(27) =1a(28) =1a(29) =18
External references
- oeis: A054120