9920000domain: NAppears in sequencesa(n) is the largest number such that all of a(n)'s length-n substrings are distinct and divisible by 80.at n=3A093280If a(n-1)=abcde..., where a,b,c,d,e... are the digits, then a(n)=abcde...+a*bcde...+ab*cde...+abc*de...+abcd*e...+....at n=18A108721a(n) = n^4*(3*n+2).at n=20A229147