890624domain: NAppears in sequencesa(n) = 2^(2*5^(n-1)) mod 10^n.at n=5A216092a(n) is the smallest number m such that the m-th triangular number ends in n zeros.at n=5A228191Numbers k such that product of divisors of k ends with k and k is nonprime (A018252).at n=28A278473