a(n) = Sum_{k=1..phi(n)-1} t(n,k)*t(n,k+1), where t(n,k) is the k-th positive integer which is coprime to n and phi(n) is the number of positive integers which are <= n and are coprime to n.
A119584
a(n) = Sum_{k=1..phi(n)-1} t(n,k)*t(n,k+1), where t(n,k) is the k-th positive integer which is coprime to n and phi(n) is the number of positive integers which are <= n and are coprime to n.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =3a(4) =20a(5) =5a(6) =70a(7) =53a(8) =121a(9) =87a(10) =330a(11) =117a(12) =572a(13) =305a(14) =507a(15) =553a(16) =1360a(17) =481a(18) =1938a(19) =873a(20) =1586a(21) =1405a(22) =3542a(23) =1241a(24) =3846a(25) =2415a(26) =4006a(27) =2765a(28) =7308a(29) =1875
External references
- oeis: A119584