%I #5 Apr 12 2018 05:18:05
%S 1,1,2,21,596,32805,2960496,396523540,73803150440,18216533196693,
%T 5757491981210470,2267526164705341925,1088820552191787545688,
%U 626169526288460672060244,424903177461959840892846066,335946105815409394263421836000,306145042287138023678922165314512
%N a(n) = [x^n] 1 + x*(1 + x*(1 + x*(1 + x*(1 + ...)^(4*n))^(3*n))^(2*n))^n.
%t Table[SeriesCoefficient[1 + x Fold[(x #1 + 1)^(n #2) &, 0, Reverse[Range[n]]], {x, 0, n}], {n, 0, 16}]
%Y Cf. A095793, A138212, A138213, A138214, A138215, A138216, A302657.
%K nonn
%O 0,3
%A _Ilya Gutkovskiy_, Apr 11 2018