-3356

Appears in sequences

• a(n) = 2^phi(n) - Sum_{j=0..n} binomial(phi(n), phi(j)).at n=20A073318
• Expansion of the unique normalized cusp form of Gamma_0(5) of weight 6 in powers of q.at n=33A226347
• G.f.: sqrt( Sum_{n>=0} 4^n*x^(n^2) ).at n=10A227293