A111227 Numbers n where A019294(n) > n.

3, 11, 29, 53, 58, 59, 67, 101, 109, 131, 149, 173, 202, 239, 461, 479, 659, 1031, 1319, 1579, 1847

Offset: 1

Author

Lambert Klasen (lambert.klasen(AT)gmx.net), Oct 26 2005

Keywords

• hard
• nonn

Comments

A number n is called (m,k)-perfect if sigma^m(n) = k*n. A019294(n) gives minimal values of m for n. a(n) are the values where A019294(n) > n.

Corresponding values of m and k are in A111726, A111727.

Links

• Graeme L. Cohen and Herman J. J. te Riele, Iterating the sum-of-divisors function Experimental Mathematics, 5 (1996), p 94.

Programs

Haskell

a111227 n = a111227_list !! (n-1)
a111227_list = filter (\x -> a019294 x > x) [1..]
-- Reinhard Zumkeller, Aug 02 2012