0,1

R. K. Guy, Unsolved Problems in Number Theory, B6.

Christophe CLAVIER, Aliquot Sequences

f := proc(n) option remember; if n = 0 then 168; else sigma(f(n-1))-f(n-1); fi; end:

Sequence in context: A060662 A059463 A038812 this_sequence A105915 A158219 A027679

Adjacent sequences: A008887 A008888 A008889 this_sequence A008891 A008892 A008893

nonn

N. J. A. Sloane (njas(AT)research.att.com).