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 A352526 #22 Apr 23 2022 14:49:00
%S A352526 2,2,12,48,480,3840,53760,645120,11612160,185794560,4087480320,
%T A352526 81749606400,2125489766400,51011754393600,1530352631808000,
%U A352526 42849873690624000,1456895705481216000,46620662575398912000,1771585177865158656000,63777066403145711616000,2678636788932119887872000
%N A352526 a(n) = Product_{k=0..n} Nimsum (2*k + 2), with Nimsum (2 + 2) = 0 replaced by 1.
%C A352526 Nimsum 2*k + 2 = A004443(2*k).
%C A352526 Sum_{n>0} 1/a(n) = 1/sqrt(e) = A092605.
%C A352526 Sum_{n>0} 1/a(2*n-1) = sinh(1/2) = A334367.
%C A352526 Sum_{n>0} 1/a(2*n) = cosh(1/2) - 2*sinh(1/2).
%C A352526 a(n)/2^n = abs(A265376(n+1)) = Product_{k=0..n} Nimsum k + 1, with Nimsum 1 + 1 = 0 replaced by 1, n > 0.
%F A352526 a(n) = 2*Product_{k=2..n} A004443(2*k).
%F A352526 a(n) = 2^(n-1)*(n+1)!/floor((n+1)/2), n > 0.
%F A352526 a(n) = 2^(n-1)*(1+(-1)^n)*((n-1)!+n!)-((-1)^n-1)*(2*n)!!/2, n > 0.
%F A352526 a(n) = 2*a(n-1)*(n+(-1)^n), n > 1, with a(1) = 2.
%t A352526 a[n_] := Product[If[k == 1, 1, BitXor[2*k, 2]], {k, 0, n}]; Array[a, 21, 0] (* _Amiram Eldar_, Mar 19 2022 *)
%o A352526 (PARI) a(n) = 2*prod(k=2,n,bitxor(2*k, 2))
%Y A352526 Cf. A004443, A092605, A265376, A334367.
%K A352526 nonn
%O A352526 0,1
%A A352526 _Peter McNair_, Mar 19 2022