a(n) = (10*n + 4)^4.

Terms

a(0) =256a(1) =38416a(2) =331776a(3) =1336336a(4) =3748096a(5) =8503056a(6) =16777216a(7) =29986576a(8) =49787136a(9) =78074896a(10) =116985856a(11) =168896016a(12) =236421376a(13) =322417936a(14) =429981696a(15) =562448656a(16) =723394816a(17) =916636176a(18) =1146228736a(19) =1416468496