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 A028363 #36 Mar 22 2021 18:23:42
%S A028363 1,30,9845550,171634285407048750,193419995622362136809061156168750,
%T A028363 14272693289804307141953423466197932293533748208968750
%N A028363 Total number of doubly-even self-dual binary codes of length 8n.
%D A028363 F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier-North Holland, 1978, p. 631.
%F A028363 a(n) = 2*Product_{i=1..4n-2} (2^i + 1).
%t A028363 Join[{1},Table[2*Product[2^i+1,{i,4n-2}],{n,6}]] (* _Harvey P. Dale_, May 08 2013 *)
%t A028363 Table[Product[2^i + 1, {i, 0, n/2 - 2}], {n, 8, 40, 8}] (* _Nathan J. Russell_, Mar 04 2016 *)
%o A028363 (Python)
%o A028363 for n in range(8, 50, 8):
%o A028363 product = 1
%o A028363 for i in range(n//2 - 1):
%o A028363 product *= 2**i + 1
%o A028363 print(product, end=", ")
%o A028363 # _Nathan J. Russell_, Mar 01 2016
%Y A028363 Cf. A003178, A003179, A028362.
%K A028363 nonn,easy,nice
%O A028363 0,2
%A A028363 _N. J. A. Sloane_
%E A028363 There is an error in Eq. (75) of F. J. MacWilliams and N. J. A. Sloane, the lower subscript should be 1 not 0.
%E A028363 Formula corrected by _N. J. A. Sloane_, May 07 2013 following a suggestion from _Harvey P. Dale_