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URL: https://oeis.org/A088825

⇱ A088825 - OEIS

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A088825
Numbers n such that the sum of largest prime factors of numbers from 1 to n is divisible by n.
4
1, 2, 8, 9, 32, 62, 558, 993, 995, 1947, 2150, 4343, 9944, 10977, 43054658, 202275890, 2291937393, 2459073795, 2836929091, 3737529738, 21382629569, 248208997602, 389691028017, 838566394212, 1019000924619
OFFSET
1,2
COMMENTS
a(21) > 15*10^9. - Donovan Johnson, Nov 01 2009
a(22) > 10^11. - Donovan Johnson, Jul 09 2010
a(26) > 5*10^12. - Giovanni Resta, Apr 25 2017
FORMULA
Solutions to Mod[A088822[x], x]=0.
MATHEMATICA
gp[n_] := If[n==1, 0, FactorInteger[n][[-1, 1]]]; Flatten@ Position[ Accumulate[ gp /@ Range[10^5]] / Range[10^5], _Integer] (* Giovanni Resta, Apr 25 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 22 2003
EXTENSIONS
More terms from Ray Chandler, Oct 31 2003
a(17)-a(20) from Donovan Johnson, Nov 01 2009
a(21) from Donovan Johnson, Jul 09 2010
a(22)-a(25) from Giovanni Resta, Apr 25 2017
STATUS
approved