Expansion of 1/(1+2*x*c(x)), c(x) the g.f. of Catalan numbers A000108.

Terms

a(0) =1a(1) =-2a(2) =2a(3) =-4a(4) =2a(5) =-12a(6) =-12a(7) =-72a(8) =-190a(9) =-700a(10) =-2308a(11) =-8120a(12) =-28364a(13) =-100856a(14) =-360792a(15) =-1301904a(16) =-4727358a(17) =-17268636a(18) =-63405012a(19) =-233885784a(20) =-866327748a(21) =-3220976616a(22) =-12016209192a(23) =-44966763504a(24) =-168750724428a(25) =-634935132312