72125

Appears in sequences

• Numerator of Sum_{k=1..n} 1/phi(k).at n=28A028415
• Duplicate of A059392.at n=4A059388
• a(1)=1; a(n) is a k(n)-almost prime; m is an A-almost prime (for 1<=A); a(n) = smallest number m>a(n-1) such that a(i)+m is an (abs[ A-k(i) ])-almost prime for i = 1,2,3,..,n-1.at n=4A059392
• Numbers k such that sigma_2(k^2 + 1) == 0 (mod k).at n=42A360105