a(n) = Sum_{k=0..m-1} T(n,k) * T(n,k+1), where m=n for n=0,1 and m=floor((n+3)/2) for n >= 2, and T given by A026022.
A027295
a(n) = Sum_{k=0..m-1} T(n,k) * T(n,k+1), where m=n for n=0,1 and m=floor((n+3)/2) for n >= 2, and T given by A026022.
Terms
- a(0) =1a(1) =4a(2) =15a(3) =52a(4) =195a(5) =676a(6) =2555a(7) =8976a(8) =34098a(9) =121448a(10) =463067a(11) =1669340a(12) =6384287a(13) =23251620a(14) =89157557a(15) =327523680a(16) =1258803182a(17) =4658150520a(18) =17940605163a(19) =66803546472a(20) =257777882894a(21) =965023761064
External references
- oeis: A027295