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a(1) = 2, a(2) = -32; a(n) = -16*a(n - 1) + 12*add(binomial(2*n - 2, 2*i)*a(i)*a(n - 1 - i), i = 1 .. n - 2).
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%I #5 Jun 23 2014 16:31:11

%S 2,-32,800,-35840,2508800,-246579200,32614400000,-5594021888000,

%T 1206137913344000,-319343506227200000,101868334198292480000,

%U -38531929483929190400000,17052425131124169113600000,-8729129668569923688857600000,5117793695169522496962560000000

%N a(1) = 2, a(2) = -32; a(n) = -16*a(n - 1) + 12*add(binomial(2*n - 2, 2*i)*a(i)*a(n - 1 - i), i = 1 .. n - 2).

%D E. Dintzl, Über die Zahlen im Koerper k(sqrt(-2)), welche den Bernoulli'schen Zahlen analog sind, Sitz. K. Akad. Wiss. Wien, Math.-Naturw. Klasse, 108 (1909), 1-29.

%p A069182 := proc(n) option remember; if n=1 then 2 elif n=2 then -32 else -16*A069182(n-1)+12*add(binomial(2*n-2,2*i)*A069182(i)*A069182(n-1-i),i=1..n-2); fi; end;

%K sign

%O 1,1

%A _N. J. A. Sloane_, Apr 13 2002