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%I #5 Dec 05 2013 19:56:18
%S 2,6,72,14040,707616000,2299654269739008000,
%T 25353370781704805143366427867873280000,
%U 3361021040447648920437074194752848938805829494939344230020451929790873600000
%N a(1) = 2, a(n+1) = a(n)*{sigma(a(n))}, where sigma(n) is the sum of the divisors function.
%C a(1) = 1, a(n+1) = a(n) + sigma(a(n)) gives A081973.
%e a(3) = 72 and sigma(72)= 195, hence a(4) = 72*195 = 14040.
%o (PARI) for(n=1,9,if(n==1,a=2,a*=sigma(a)); print(a); )
%Y Cf. A064491, A081973, A085864.
%K nonn
%O 1,1
%A _Amarnath Murthy_, Jul 06 2003
%E More terms from _Ray Chandler_, Jul 16 2003
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