a(n) = (5n+1)^5.

Terms

a(0) =1a(1) =7776a(2) =161051a(3) =1048576a(4) =4084101a(5) =11881376a(6) =28629151a(7) =60466176a(8) =115856201a(9) =205962976a(10) =345025251a(11) =550731776a(12) =844596301a(13) =1252332576a(14) =1804229351a(15) =2535525376a(16) =3486784401a(17) =4704270176a(18) =6240321451