Expansion of (1+x^2*C^2)*C^2, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.

A071721

Expansion of (1+x^2*C^2)*C^2, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =18a(4) =56a(5) =180a(6) =594a(7) =2002a(8) =6864a(9) =23868a(10) =83980a(11) =298452a(12) =1069776a(13) =3863080a(14) =14040810a(15) =51325650a(16) =188574240a(17) =695987820a(18) =2579248980a(19) =9593714460a(20) =35804293200a(21) =134032593240a(22) =503154100020

External references