Numerator of binomial(2*n,n)/20^n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =7a(5) =63a(6) =231a(7) =429a(8) =1287a(9) =2431a(10) =46189a(11) =88179a(12) =676039a(13) =52003a(14) =200583a(15) =1938969a(16) =60108039a(17) =116680311a(18) =90751353a(19) =176726319a(20) =6892326441a(21) =13456446861a(22) =52602474093a(23) =20583576819a(24) =322476036831