Year numbers, i.e., phi(n) = 2 phi(sigma(n)), divisible by a 5th prime power.

A137819

Year numbers, i.e., phi(n) = 2 phi(sigma(n)), divisible by a 5th prime power.

Terms

    a(0) =1811079a(1) =4473387a(2) =67009923a(3) =77242167a(4) =88605819a(5) =110475819a(6) =120781449a(7) =132208767a(8) =134082297a(9) =165515319a(10) =183408867a(11) =225548469a(12) =232275681a(13) =272876607a(14) =284339403a(15) =326557251a(16) =349538247a(17) =402371793a(18) =425844621a(19) =501668883a(20) =566867727

External references