Numbers n such that phi(phi(n)) + sigma(sigma(n)) = phi(sigma(n)) + sigma(phi(n)), where phi=A000010 is Euler's totient function and sigma=A000203 is the sum of divisors function.
A066850
Numbers n such that phi(phi(n)) + sigma(sigma(n)) = phi(sigma(n)) + sigma(phi(n)), where phi=A000010 is Euler's totient function and sigma=A000203 is the sum of divisors function.
Terms
- a(0) =1a(1) =4a(2) =2669a(3) =9559a(4) =15293a(5) =32583a(6) =36593a(7) =38443a(8) =255367a(9) =257239a(10) =273977a(11) =283391a(12) =314101a(13) =421553a(14) =488363a(15) =532975a(16) =768699a(17) =839973a(18) =871757a(19) =1960479a(20) =2337221a(21) =2374867a(22) =3084659a(23) =3326653a(24) =3735029a(25) =4440017a(26) =5387373a(27) =7930439a(28) =8114377
External references
- oeis: A066850