8*P_4(2n), 8 times the Legendre Polynomial of order 4 at 2n.

Terms

a(0) =3a(1) =443a(2) =8483a(3) =44283a(4) =141443a(5) =347003a(6) =721443a(7) =1338683a(8) =2286083a(9) =3664443a(10) =5588003a(11) =8184443a(12) =11594883a(13) =15973883a(14) =21489443a(15) =28323003a(16) =36669443a(17) =46737083a(18) =58747683a(19) =72936443a(20) =89552003a(21) =108856443a(22) =131125283a(23) =156647483a(24) =185725443a(25) =218675003a(26) =255825443