a(0) = 0, a(n) = smallest composite k such that phi(k + 2^n) = phi(k) + 2^n; also cototient(k + 2^n) = cototient(k).

A063104

a(0) = 0, a(n) = smallest composite k such that phi(k + 2^n) = phi(k) + 2^n; also cototient(k + 2^n) = cototient(k).

Terms

    a(0) =0a(1) =6a(2) =12a(3) =24a(4) =39a(5) =84a(6) =69a(7) =75a(8) =213a(9) =1092a(10) =249a(11) =1131a(12) =8736a(13) =13413a(14) =21201a(15) =1275a(16) =2193a(17) =279552a(18) =98337a(19) =968727a(20) =71085a(21) =2783555a(22) =646869a(23) =3145959a(24) =1805781a(25) =5798435a(26) =787605a(27) =27962075a(28) =2073033a(29) =282181709

External references