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E.g.f. satisfies A(x) = 1/(3 - 2*exp(x*A(x)^2)).
1

%I #8 Mar 18 2024 11:46:37

%S 1,2,26,674,26682,1429682,96867178,7946279490,765861255002,

%T 84837503946962,10621798904563530,1483378875680954210,

%U 228626616449674796602,38549099486166110798322,7058696888173770772536362,1394913467379909728350803074,295904373562519633314958421274

%N E.g.f. satisfies A(x) = 1/(3 - 2*exp(x*A(x)^2)).

%F a(n) = (1/(2*n+1)!) * Sum_{k=0..n} 2^k * (2*n+k)! * Stirling2(n,k).

%o (PARI) a(n) = sum(k=0, n, 2^k*(2*n+k)!*stirling(n, k, 2))/(2*n+1)!;

%Y Cf. A004123, A258922.

%Y Cf. A367134.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Mar 18 2024