a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A026536.
A027268
a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A026536.
Terms
- a(0) =0a(1) =6a(2) =20a(3) =180a(4) =644a(5) =5502a(6) =20292a(7) =174456a(8) =654632a(9) =5673140a(10) =21528000a(11) =187675644a(12) =717800628a(13) =6284986554a(14) =24178479500a(15) =212408191568a(16) =820811282352
External references
- oeis: A027268