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

Terms

a(0) =1a(1) =257a(2) =10257a(3) =170257a(4) =1670882a(5) =11505378a(6) =61292514a(7) =268652514a(8) =1009853139a(9) =3352413139a(10) =10042998755a(11) =27598188771a(12) =70457539396a(13) =168802499396a(14) =382616259396a(15) =825980472132