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%I #35 Sep 08 2022 08:46:18
%S 1,5,133,8425,968561,175694701,46142992981,16549469742737,
%T 7769425693383361,4623280765312793221,3400130923182845767301,
%U 3028135414242749262553465,3211431367839213404127361393,3999028255132797763368898027805,5777573340599982456777597457984981
%N a(n) = (n^(2n) - (n-1)^(2n))/(2n-1).
%C n such that a(n) is divisible by a square > 1: 4, 15, 22, 27, ...
%e a(2) = 5 because (2^(2*2) - (2-1)^(2*2))/(2*2-1) = 5.
%o (Magma) [(n^(2*n) - (n-1)^(2*n))/(2*n-1): n in [1..15]];
%Y Cf. A280302.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, Jan 03 2017
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