Numbers that require a record number of iterations of the sum of odd divisors function (A000593) to reach 1.

A320641

Numbers that require a record number of iterations of the sum of odd divisors function (A000593) to reach 1.

Terms

    a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =17a(6) =67a(7) =193a(8) =1069a(9) =2137a(10) =4273a(11) =34183a(12) =205097a(13) =990361a(14) =11884331a(15) =38294881a(16) =76589761a(17) =574396453a(18) =10339136153a(19) =36177024721a(20) =72354049441a(21) =144708098881

External references