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%I #5 Jan 22 2024 10:42:59
%S 1,3,9,35,141,745,3955,23985,155527,1060941,7393765,53041015,
%T 387815175,2882682967,21715452927,165583974835,1275674593889,
%U 9918184576835,77738274996385,613753581566079,4877383708962749,38989308129231703,313354624116918229,2530796548734844153
%N a(n) is the constant term in expansion of Product_{k=1..n} (x^(k^2) + 1 + 1/x^(k^2))^2.
%t Table[Coefficient[Product[(x^(k^2) + 1 + 1/x^(k^2))^2, {k, 1, n}], x, 0], {n, 0, 23}]
%Y Cf. A047653, A156181, A350249, A350495.
%K nonn
%O 0,2
%A _Ilya Gutkovskiy_, Jan 22 2024