Dropping first and last digit of n leaves its largest prime factor.

Terms

a(0) =128a(1) =150a(2) =175a(3) =250a(4) =378a(5) =432a(6) =450a(7) =672a(8) =750a(9) =875a(10) =1024a(11) =1197a(12) =1537a(13) =1593a(14) =1675a(15) =2112a(16) =2176a(17) =2596a(18) =3179a(19) =3192a(20) =3478a(21) =3792a(22) =3977a(23) =4050a(24) =4199a(25) =4232a(26) =4895a(27) =5412a(28) =5612a(29) =6171