666664

Appears in sequences

• Numbers n such that every digit of both n and n^2 contains a loop (only digits 0,4,6,8,9 in n and n^2).at n=37A107626
• Numbers k such that k and k^2 use only the digits 0, 4, 6, 8 and 9.at n=38A136956
• For k in {2,3,...,9} define a sequence as follows: a(0)=0; for n>=0, a(n+1)=a(n)+1, unless a(n) ends in k, in which case a(n+1) is obtained by replacing the last digit of a(n) with the digit(s) of k^2. This is k(8).at n=29A237345