%I #5 May 21 2017 07:49:30

%S 1,1,33,3393,715329,255419649,138324673377,105723078203457,

%T 108400924932329601,143589514674637260801,238670525628280806487713,

%U 486411018516606613409744193,1192731112687557517714202303169,3464267964203640308372312350830849,11761665286319167564660531957187772897,46153563625764407361666349419808431496257,207288280492672493893642973836751374267592961

%N E.g.f. C(x) satisfies: C(x) = cosh( Integral C(x)^8 dx ).

%F C(x)^2 - S(x)^2 = 1 and C(x) = 1 + Integral C(x)^8*S(x) dx, where S(x) is described by A281439.

%o (PARI) {a(n) = my(S=x, C=1); for(i=0, n, S = intformal( C^9 +x*O(x^(2*n))); C = 1 + intformal( S*C^8 ) ); (2*n)!*polcoeff(C, 2*n)}

%o for(n=0, 30, print1(a(n), ", "))

%K nonn

%O 0,3

%A _Paul D. Hanna_, Jan 21 2017