G.f. is G(x*(1-x)/(1-2*x)) where G(x) is g.f. for Catalan numbers A000108.

A059278

G.f. is G(x*(1-x)/(1-2*x)) where G(x) is g.f. for Catalan numbers A000108.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =11a(4) =43a(5) =175a(6) =735a(7) =3167a(8) =13935a(9) =62383a(10) =283311a(11) =1302271a(12) =6047679a(13) =28332991a(14) =133752191a(15) =635618431a(16) =3038326911a(17) =14599154431a(18) =70474889471a(19) =341624867071

External references