890445

Appears in sequences

• 2nd elementary symmetric function of the first n+1 positive integers congruent to 2 mod 3.at n=28A024391
• Odd composite numbers k such that cototient(k) - phi(k) = k - 2*phi(k) is an odd prime.at n=25A083255
• Triangular numbers obtained as the concatenation of 2*k and k.at n=7A226742
• a(n) is the largest triangular number that is the concatenation of two n-digit numbers 2*x and x.at n=2A380792