a(n) = (n+1)^2*(n+2)^2*(n+3)^2*(n+4)/144.

Terms

a(0) =1a(1) =20a(2) =150a(3) =700a(4) =2450a(5) =7056a(6) =17640a(7) =39600a(8) =81675a(9) =157300a(10) =286286a(11) =496860a(12) =828100a(13) =1332800a(14) =2080800a(15) =3162816a(16) =4694805a(17) =6822900a(18) =9728950a(19) =13636700a(20) =18818646a(21) =25603600a(22) =34385000a(23) =45630000a(24) =59889375a(25) =77808276a(26) =100137870a(27) =127747900