Largest prime <= n!.

Terms

a(0) =2a(1) =5a(2) =23a(3) =113a(4) =719a(5) =5039a(6) =40289a(7) =362867a(8) =3628789a(9) =39916787a(10) =479001599a(11) =6227020777a(12) =87178291199