Least integer m > 0 with pi(m*n) = phi(m) + phi(n), where pi(.) is the prime-counting function and phi(.) is Euler's totient function.
A247672
Least integer m > 0 with pi(m*n) = phi(m) + phi(n), where pi(.) is the prime-counting function and phi(.) is Euler's totient function.
Terms
- a(0) =6a(1) =2a(2) =2a(3) =23a(4) =3a(5) =1a(6) =3a(7) =1033a(8) =2a(9) =6449a(10) =15887a(11) =1a(12) =100169a(13) =268393a(14) =636917a(15) =2113589a(16) =70324093a(17) =1a(18) =27852457a(19) =78848479a(20) =2a(21) =468329417a(22) =4a(23) =1a(24) =10220118551
External references
- oeis: A247672