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%I #8 Jun 26 2024 21:57:13
%S 0,0,0,2,0,7,0,4,6,11,0,12,0,15,19,8,0,17,0,18,26,21,0,22,15,25,12,26,
%T 0,39,0,12,37,31,41,29,0,35,44,36,0,55,0,38,38,41,0,36,28,38,55,44,0,
%U 39,58,46,62,49,0,69,0,53,52,22,69,79,0,56,73,80,0,49,0,61
%N a(n) = Sum_{p|n, p prime} p * pi(n/p).
%F a(p^k) = p * pi(p^(k-1)), for p prime and k >= 1. - _Wesley Ivan Hurt_, Jun 26 2024
%t Table[DivisorSum[n, #*PrimePi[n/#] &, PrimeQ[#] &], {n, 100}]
%Y Cf. A000720 (pi), A066328.
%K nonn,easy
%O 1,4
%A _Wesley Ivan Hurt_, Jan 30 2024