OFFSET
1,2
FORMULA
C(x)^2 - S(x)^2 = 1 and S'(x) = C(x)^8, where C(x) is described by A281440.
MATHEMATICA
a[n_] := Module[{S = x, C = 1, C8, SC7}, For[i = 1, i <= n, i++, C8 = C^8 + x*O[x]^(2n) // Normal; S = Integrate[C8 , x]; SC7 = S*C^7 + O[x]^(2n) // Normal; C = 1+Integrate[SC7, x]]; (2n-1)!*Coefficient[S, x, 2n-1]]; Array[a, 17] (* Jean-François Alcover, Mar 01 2017, translated from Pari *)
PROG
(PARI) {a(n) = my(S=x, C=1); for(i=1, n, S = intformal( C^8 +x*O(x^(2*n))); C = 1 + intformal( S*C^7 ) ); (2*n-1)!*polcoeff(S, 2*n-1)}
for(n=1, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 21 2017
STATUS
approved