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%I #5 Jun 28 2021 17:37:37
%S 0,2,3,4,5,5,7,4,9,7,11,7,13,9,8,4,17,11,19,9,10,13,23,7,25,15,9,11,
%T 29,10,31,4,14,19,12,13,37,21,16,9,41,12,43,15,14,25,47,7,49,27,20,17,
%U 53,11,16,11,22,31,59,12,61,33,16,4,18,16,67,21,26,14,71,13,73,39,28
%N a(n) = Sum_{p|n, p prime} p * gcd(p,n/p).
%C If p is prime, a(p) = Sum_{p|p} p * gcd(p,p/p) = p * 1 = p.
%e a(18) = Sum_{p|18} p * gcd(p,18/p) = 2*gcd(2,9) + 3*gcd(3,6) = 2*1 + 3*3 = 11.
%t Table[Sum[k*GCD[k, n/k] (PrimePi[k] - PrimePi[k - 1]) (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 100}]
%Y Cf. A345266.
%K nonn
%O 1,2
%A _Wesley Ivan Hurt_, Jun 13 2021
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