Composite numbers n such that Sum_{d_<n | n} phi(d_<n) / (d_<n) is an integer, where d_<n = divisors of n that are less than n, phi(x) = A000010(x).
A211778
Composite numbers n such that Sum_{d_<n | n} phi(d_<n) / (d_<n) is an integer, where d_<n = divisors of n that are less than n, phi(x) = A000010(x).
Terms
- a(0) =8a(1) =12a(2) =32a(3) =80a(4) =81a(5) =128a(6) =189a(7) =196a(8) =324a(9) =336a(10) =448a(11) =512a(12) =576a(13) =768a(14) =1600a(15) =1936a(16) =2025a(17) =2048a(18) =2187a(19) =2500a(20) =5292a(21) =5324a(22) =5616a(23) =5780a(24) =8192a(25) =8748a(26) =9477a(27) =11264a(28) =12096a(29) =13520
External references
- oeis: A211778