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%I #10 Aug 17 2019 01:15:31
%S 0,3,5,7,3,11,13,8,17,19,10,23,5,3,29,31,14,12,37,16,41,43,8,47,7,20,
%T 53,16,22,59,61,10,18,67,26,71,73,8,18,79,3,83,22,32,89,20,34,24,97,
%U 14,101,103,15,107,109,40,113,28,16,24,11,44,5,127,46,131,26,8,137,139,50,24
%N Bisection of A008472.
%C The sum of the distinct primes dividing 2n-1. - _Emeric Deutsch_, Mar 11 2005
%e a(23)=8 because 45=3^2*5 and 3+5=8.
%p with(numtheory): a:=proc(n) local b: b:=convert(factorset(2*n-1),list): add(b[j],j=1..nops(b)) end: seq(a(n),n=1..80); # _Emeric Deutsch_, Mar 11 2005
%t Join[{0},Total[Transpose[FactorInteger[#]][[1]]]&/@(2*Range[2,80]-1)] (* _Harvey P. Dale_, Aug 05 2015 *)
%K nonn,easy
%O 1,2
%A _N. J. A. Sloane_, Nov 20 2004
%E More terms from _Emeric Deutsch_, Mar 11 2005
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