Coefficient of x^n in the expansion of 1 / (1-x-x^4)^n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =10a(4) =39a(5) =156a(6) =630a(7) =2556a(8) =10431a(9) =42823a(10) =176748a(11) =732810a(12) =3049722a(13) =12732188a(14) =53299284a(15) =223645200a(16) =940355391a(17) =3961092906a(18) =16712516565a(19) =70615352330a(20) =298761296064