0,1

f(x) = sum of prime factors with multiplicity, so that f(1500) = 2+2+3+5+5+5 = 22.

Identical to the different-offset A121360 except for the second term. - Hans Havermann, Oct 05 2010

a(20) <= 536226160966. a(21) <= 2681130804805. a(22) <= 8512643845707. - Donovan Johnson

Table of n, a(n) for n=0..19.

Sequence in context: A022112 A107019 A269831 * A199697 A135619 A067795

Adjacent sequences: A048130 A048131 A048132 * A048134 A048135 A048136

nonn

David W. Wilson

a(17) from Donovan Johnson, Apr 25 2010

Edited comment and a(18)-a(19) from Donovan Johnson, Oct 16 2010

approved