Denominator of sum(1/(phi(k)sigma(k)),k=1..n), where phi(k) is the totient function and sigma(k) is the sum of the divisors function.

A104527

Denominator of sum(1/(phi(k)sigma(k)),k=1..n), where phi(k) is the totient function and sigma(k) is the sum of the divisors function.

Terms

    a(0) =1a(1) =3a(2) =24a(3) =168a(4) =7a(5) =168a(6) =112a(7) =1680a(8) =21840a(9) =65520a(10) =65520a(11) =16380a(12) =32760a(13) =21840a(14) =29120a(15) =902720a(16) =8124480a(17) =8124480a(18) =1624896a(19) =1624896a(20) =3249792a(21) =5416320a(22) =59579520a(23) =59579520a(24) =59579520a(25) =178738560a(26) =178738560a(27) =178738560a(28) =178738560a(29) =178738560

External references