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%I #18 Apr 27 2014 07:11:37
%S 1,3,225,250047,4228250625,1120413075641343,4715453174592516890625,
%T 316777275155162685106909462527,
%U 340240830764391036687105719527812890625,5845805845679338940092384222659294205213252255743,1606922719369349023077959288770050490334792256259918212890625
%N (4^n - 1)^n.
%F (4^n - 1)^n
%e a(3) = 63^3 = 250047.
%o (PARI) a(n) = (4^n - 1)^n; \\ _Michel Marcus_, Apr 16 2014
%Y Cf. A055601, A060613, A241095, A240091.
%K nonn
%O 0,2
%A _Hannah Ko_, Apr 15 2014