a(n) = floor(log(n!)).

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =4a(5) =6a(6) =8a(7) =10a(8) =12a(9) =15a(10) =17a(11) =19a(12) =22a(13) =25a(14) =27a(15) =30a(16) =33a(17) =36a(18) =39a(19) =42a(20) =45a(21) =48a(22) =51a(23) =54a(24) =58a(25) =61a(26) =64a(27) =67a(28) =71a(29) =74