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 A138334 #8 Sep 08 2022 08:45:33
%S A138334 -1024,14336,-106496,559104,-2329600,8200192,-25346048,70606848,
%T A138334 -180590592,429977600,-963149824,2046693376,-4153583616,8094162944,
%U A138334 -15214592000,27690557440,-48952949760,84293314560,-141710499840,233076480000
%N A138334 C(n+11, 11)*(n+6)*(-1)^(n+1)*512/3.
%C A138334 Seventh column of the triangle defined in A123588, thirteenth column of the triangle defined in A123583.
%H A138334 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a>
%F A138334 a(n) = coefficient of x^12 in the polynomial 1 - T_(n+6)(x)^2, where T_n(x) is the n-th Chebyshev polynomial of the first kind.
%F A138334 G.f.: 1024*(x-1)/(x+1)^13.
%t A138334 Table[Binomial[n+11,11](n+6)(-1)^(n+1) 512/3,{n,0,20}] (* _Harvey P. Dale_, Jun 03 2021 *)
%o A138334 (Magma) [ Binomial(n+11, 11)*(n+6)*(-1)^(n+1)*512/3: n in [0..19] ];
%o A138334 (Magma) k:=6; [ Coefficients(1-ChebyshevT(n+k)^2)[2*k+1]: n in [0..19] ];
%o A138334 (PARI) for(n=0,19,print1(polcoeff(taylor(1024*(x-1)/(x+1)^13,x),n),","));
%Y A138334 Cf. A007318 (Pascal's triangle), A123588, A123583.
%K A138334 sign
%O A138334 0,1
%A A138334 _Klaus Brockhaus_, Mar 15 2008