a(n) is the greatest prime factor of n^n - n!.

Terms

a(0) =2a(1) =7a(2) =29a(3) =601a(4) =29a(5) =116929a(6) =11887a(7) =4778489a(8) =82207a(9) =296987a(10) =2767a(11) =464089a(12) =36922117a(13) =71722471217a(14) =10219277051a(15) =9406703479a(16) =2040247819a(17) =122450719a(18) =1265072927a(20) =21514105057a(21) =46999724987a(22) =29693667067a(24) =692132186353