405449

Appears in sequences

• a(1)=1, a(n)=a(n-1)+n^1 if n odd, a(n)=a(n-1)+ n^4 if n is even.at n=20A140146
• Numbers n such that sigma(n)/phi(n) = 36/25.at n=5A164649
• Numbers such that the sum of the squares of the largest and the smallest prime divisor equals the sum of the squares of the other distinct prime divisors.at n=11A199857