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%I #6 Nov 21 2013 12:48:10
%S 0,0,0,1,0,2,0,5,4,2,0,8,0,6,8,11,0,14,0,14,12,8,0,20,18,10,20,16,0,
%T 24,0,29,20,14,24,28,0,18,24,32,0,34,0,32,38,20,0,44,40,42,30,34,0,50,
%U 42,46,34,24,0,54,0,30,54,59,48,50,0,50,44,60,0,68,0,36,68,54,62,60,0,74
%N (greatest prime <= n) - (greatest prime factor of n).
%C a(n) = A007917(n) - A006530(n);
%C n>1: a(n) = 0 iff n is prime.
%t Join[{0},Table[NextPrime[n+1,-1]-FactorInteger[n][[-1,1]],{n,2,90}]] (* _Harvey P. Dale_, Nov 27 2011 *)
%Y Cf. A083718, A083715, A083716, A083717.
%K nonn
%O 1,6
%A _Reinhard Zumkeller_, May 04 2003