Numbers k such that sigma(phi(k))-phi(sigma(k)) is nonzero and is divisible by (k-1), that is A065395(k)/(k-1) = (phi(sigma(k))-sigma(phi(k)))/(k-1) is a nonzero integer.
A092585
Numbers k such that sigma(phi(k))-phi(sigma(k)) is nonzero and is divisible by (k-1), that is A065395(k)/(k-1) = (phi(sigma(k))-sigma(phi(k)))/(k-1) is a nonzero integer.
Terms
- a(0) =2a(1) =4a(2) =16a(3) =64a(4) =151a(5) =449a(6) =3403a(7) =4096a(8) =4267a(9) =9307a(10) =35905a(11) =65536a(12) =247285a(13) =262144a(14) =17625601a(15) =33126625a(16) =399288961a(17) =649232833a(18) =947278081a(19) =1073741824a(20) =2102485441a(21) =4555788385a(22) =5203567081a(23) =6103058177a(24) =7115716609
External references
- oeis: A092585