OFFSET
1,2
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = Pi^2/12 * n^2/log n + O(n^2/log^2 n). - Charles R Greathouse IV, Feb 19 2014
a(n) ~ zeta(2) * A088821(n), where zeta(2) = Pi^2/6. - Thomas Ordowski, Nov 29 2018
MATHEMATICA
-1 + Accumulate@ Array[FactorInteger[#][[-1, 1]] &, 57] (* Michael De Vlieger, Jul 23 2017 *)
PROG
(PARI) gpf(n)=if(n<4, n, n=factor(n)[, 1]; n[#n])
a(n)=sum(k=2, n, gpf(k)) \\ Charles R Greathouse IV, Feb 19 2014
(GAP) P:=List(List([2..60], n->Reversed(Factors(n))), i->i[1]);;
a:=Concatenation([0], List([1..Length(P)], i->Sum([1..i], k->P[k]))); # Muniru A Asiru, Nov 29 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 22 2003
STATUS
approved