a(n) is the least number k such that the equation phi(x) = k has exactly n solutions and the arithmetic mean of these solutions is an integer, or -1 if no such number exists.
A389860
a(n) is the least number k such that the equation phi(x) = k has exactly n solutions and the arithmetic mean of these solutions is an integer, or -1 if no such number exists.
Terms
- a(0) =6a(1) =8a(2) =1232a(3) =32a(4) =464a(5) =2064a(6) =1640a(7) =6816a(8) =2464a(9) =2940a(10) =3480a(11) =16400a(12) =4928a(13) =1560a(14) =6360a(15) =6880a(16) =24528a(17) =61952a(18) =2208a(19) =26712a(20) =18624a(21) =4000a(22) =93440a(23) =17928a(24) =184448a(25) =76480a(26) =27552a(27) =16192a(28) =59200a(29) =21000
External references
- oeis: A389860