41164

Appears in sequences

• a(n) is the concatenation of n and 4n.at n=40A019552
• Numbers n such that sigma(n+1)+sigma(n)=3n.at n=7A067806
• Numbers k such that (sigma(k)+sigma(k+1))/k is an integer.at n=9A068078
• Numbers k such that sigma(sigma(k) - k) = phi(sigma(k) + k).at n=23A074886
• Sum of divisors of n and product of divisors of n are both perfect cubes.at n=12A244428
• Expansion of Product_{k>=0} (1+x^(3*k+1))^4.at n=47A261637
• Triangle read by rows: coefficients of the polynomial (Sum_{i=0..k} (Product_{j=0..i} (x+j)))/(x*(x+2)).at n=30A270250
• a(n) = 2*(3*n+1)*(9*n+8).at n=27A304506