57055

Appears in sequences

• Numbers k such that k and k^2 use only the digits 0, 2, 3, 5 and 7.at n=29A136889
• G.f.: Sum_{n>=0} Product_{k=1..n} ((1+2*x)^k - 1)/((1+2*x)^k + 1).at n=9A208816