Number of digits in 7^(n!).

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =102a(6) =609a(7) =4260a(8) =34075a(9) =306670a(10) =3066692a(11) =33733610a(12) =404803314a(13) =5262443074a(14) =73674203025