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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

%I

%S 1,2,8,9,32,62,558,993,995,1947,2150,4343,9944,10977,43054658,

%T 202275890,2291937393,2459073795,2836929091,3737529738,21382629569,

%U 248208997602,389691028017,838566394212,1019000924619

%N Numbers n such that the sum of largest prime factors of numbers from 1 to n is divisible by n.

%C a(21) > 15*10^9. - _Donovan Johnson_, Nov 01 2009

%C a(22) > 10^11. - _Donovan Johnson_, Jul 09 2010

%C a(26) > 5*10^12. - _Giovanni Resta_, Apr 25 2017

%F Solutions to Mod[A088822[x], x]=0.

%t 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 *)

%Y Cf. A088821-A088824.

%K nonn

%O 1,2

%A _Labos Elemer_, Oct 22 2003

%E More terms from _Ray Chandler_, Oct 31 2003

%E a(17)-a(20) from _Donovan Johnson_, Nov 01 2009

%E a(21) from _Donovan Johnson_, Jul 09 2010

%E a(22)-a(25) from _Giovanni Resta_, Apr 25 2017

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Last modified June 14 08:31 EDT 2021. Contains 345018 sequences. (Running on oeis4.)