a(n) = Sum_{i=1..n} C(i+3,4)^2.

Terms

a(0) =1a(1) =26a(2) =251a(3) =1476a(4) =6376a(5) =22252a(6) =66352a(7) =175252a(8) =420277a(9) =931502a(10) =1933503a(11) =3796728a(12) =7109128a(13) =12773528a(14) =22137128a(15) =37160504a(16) =60634529a(17) =96454754a(18) =149963979a(19) =228375004a(20) =341286880a(21) =501309380a(22) =724811880a(23) =1032814380a(24) =1452040005a(25) =2016150006a(26) =2767184031a(27) =3757230256