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 A367809 #8 Dec 01 2023 18:50:41
%S A367809 1,0,7,-17,166,-931,8333,-67902,668341,-6733957,74909152,-875130273,
%T A367809 10931723505,-143624036492,1989841289619,-28881136161245,
%U A367809 438657928012966,-6948176832355895,114571387874994353,-1962292996833874918,34849770255925089153,-640681440719312240225,12174584322610783966760
%N A367809 a(n) = Sum_{k=0..n} A011971(n, k) * (-2)^(n - k).
%C A367809 The Peirce/Aitken polynomials evaluated at -1/2 and the result normalized with (-2)^n.
%o A367809 (Python) # Using the function b from A367808.
%o A367809 def a(n): return sum(b(n)[k] * (-2) ** (n - k) for k in range(n + 1))
%o A367809 print([a(n) for n in range(23)])
%Y A367809 Cf. A011971, A367808.
%K A367809 sign
%O A367809 0,3
%A A367809 _Peter Luschny_, Dec 01 2023