Main diagonal of symmetric array defined by the recurrence T(n,1)=1, T(1,k)=1, for n >= k: T(n,k) = Sum_{i=1..k-1} T(n-i,k), for n < k: T(n,k) = Sum_{i=1..n-1} T(k-i,n).

A212263

Main diagonal of symmetric array defined by the recurrence T(n,1)=1, T(1,k)=1, for n >= k: T(n,k) = Sum_{i=1..k-1} T(n-i,k), for n < k: T(n,k) = Sum_{i=1..n-1} T(k-i,n).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =16a(5) =58a(6) =222a(7) =869a(8) =3438a(9) =13672a(10) =54518a(11) =217706a(12) =870036a(13) =3478446a(14) =13910128a(15) =55632657a(16) =222513784a(17) =890019102a(18) =3559999490a(19) =14239834188a(20) =56958988812a(21) =227835217794a(22) =911339311462

External references