a(n) = Sum_{k=1, n} phi(k)*index(k, n), with phi(k) the Euler totient A000010(k) and index(k,n) the position of 1/k in the n-th row of the Farey sequence of order k, A049805(n,k).
A244396
a(n) = Sum_{k=1, n} phi(k)*index(k, n), with phi(k) the Euler totient A000010(k) and index(k,n) the position of 1/k in the n-th row of the Farey sequence of order k, A049805(n,k).
Terms
- a(0) =2a(1) =5a(2) =12a(3) =21a(4) =39a(5) =54a(6) =87a(7) =117a(8) =162a(9) =204a(10) =279a(11) =333a(12) =435a(13) =516a(14) =624a(15) =732a(16) =900a(17) =1017a(18) =1224a(19) =1380a(20) =1590a(21) =1785a(22) =2082a(23) =2286a(24) =2616a(25) =2886a(26) =3237a(27) =3543a(28) =4005a(29) =4305
External references
- oeis: A244396