A026304 a(n) = T(4n,n), where T is the array in A026300.
1, 4, 35, 340, 3484, 36784, 395922, 4319172, 47588100, 528328108, 5901043161, 66233871972, 746434573208
Offset: 0
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.