a(n) = denominator(Sum_{k=1..n} 1/P(k)), where P(k) = A006530(k) is the greatest prime dividing k for k >= 2, and P(1) = 1.

A378679

a(n) = denominator(Sum_{k=1..n} 1/P(k)), where P(k) = A006530(k) is the greatest prime dividing k for k >= 2, and P(1) = 1.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =3a(4) =15a(5) =15a(6) =105a(7) =210a(8) =70a(9) =70a(10) =770a(11) =2310a(12) =30030a(13) =30030a(14) =30030a(15) =15015a(16) =255255a(17) =255255a(18) =4849845a(19) =4849845a(20) =4849845a(21) =4849845a(22) =111546435a(23) =37182145a(24) =7436429a(25) =7436429a(26) =22309287a(27) =22309287a(28) =646969323a(29) =3234846615

External references