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.
%I A135757 #20 Sep 08 2022 08:45:32
%S A135757 1,2,20,924,184756,155117520,538257874440,7648690600760440,
%T A135757 442512540276836779204,103827421287553411369671120,
%U A135757 98527218530093856775578873054432,377389666165540953244592352291892721700,5825874245311064218315521996517139009907512400
%N A135757 Central binomial coefficients at triangular positions: a(n) = A000984(n(n+1)/2).
%H A135757 G. C. Greubel, <a href="/A135757/b135757.txt">Table of n, a(n) for n = 0..50</a>
%F A135757 a(n) = binomial(n(n+1), n(n+1)/2).
%F A135757 a(n) ~ 2^(n^2+n) sqrt(2/Pi) (1/n - 1/(2n^2) + 1/(8n^3) + ...). - _Robert Israel_, Nov 08 2016
%p A135757 seq(binomial(n*(n+1),n*(n+1)/2),n=0..20); # _Robert Israel_, Nov 08 2016
%t A135757 Table[Binomial[n*(n + 1), n*(n + 1)/2], {n,0,10}] (* _G. C. Greubel_, Nov 07 2016 *)
%o A135757 (PARI) a(n)=binomial(n*(n+1),n*(n+1)/2)
%o A135757 (Magma) [Binomial(n*(n+1), n*(n+1) div 2): n in [0..15]]; // _Vincenzo Librandi_, Nov 08 2016
%Y A135757 Cf. A000984, A135758.
%K A135757 nonn,easy
%O A135757 0,2
%A A135757 _Paul D. Hanna_, Dec 02 2007