13286025

Appears in sequences

• a(n) = (2n + 1)*3^n.at n=12A124647
• Odd solutions of phi(sigma(k)) = sigma(phi(k)).at n=10A159939
• Expansion of (1+27x^2-54x^3)/((1+3x)^2*(1-3x+9 x^2)).at n=12A168075
• Numbers with 39 divisors.at n=16A175748
• a(n) is the smallest integer having exactly n odd square divisors (A298735).at n=13A357450
• a(n) = (n + 1)^(n - 2)*(3*n + 1).at n=8A367255