a(n) = Sum_{k=0..m-1} T(n,k) * T(n,k+1), where m=n for n=0,1,2,3; m=2n for n >= 4; and T is given by A026082.
A027316
a(n) = Sum_{k=0..m-1} T(n,k) * T(n,k+1), where m=n for n=0,1,2,3; m=2n for n >= 4; and T is given by A026082.
Terms
- a(0) =1a(1) =4a(2) =15a(3) =70a(4) =644a(5) =5502a(6) =46936a(7) =402164a(8) =3460536a(9) =29885592a(10) =258897792a(11) =2248831350a(12) =19579288052a(13) =170814593158
External references
- oeis: A027316