a(n) = (12*n + 3)^5.

Terms

a(0) =243a(1) =759375a(2) =14348907a(3) =90224199a(4) =345025251a(5) =992436543a(6) =2373046875a(7) =4984209207a(8) =9509900499a(9) =16850581551a(10) =28153056843a(11) =44840334375a(12) =68641485507a(13) =101621504799a(14) =146211169851a(15) =205236901143a(16) =281950621875a(17) =380059617807a(18) =503756397099a(19) =657748550151a(20) =847288609443