a(n) = Sum_{k=0..2*n-2} T(n, k)*T(n, k+2), T given by A027960.
A027986
a(n) = Sum_{k=0..2*n-2} T(n, k)*T(n, k+2), T given by A027960.
Terms
- a(0) =20a(1) =100a(2) =420a(3) =1694a(4) =6746a(5) =26735a(6) =105722a(7) =417613a(8) =1648692a(9) =6507197a(10) =25681362a(11) =101359219a(12) =400094756a(13) =1579568360a(14) =6237401648a(15) =24635828774a(16) =97327071806a(17) =384596629610
External references
- oeis: A027986