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%I #5 Jan 20 2024 16:22:49
%S 1,1,1,1,6,6,13,13,13,13,24,24,37,37,37,37,54,54,73,73,73,73,96,96,
%T 121,121,121,121,150,150,181,181,181,181,216,216,253,253,253,253,294,
%U 294,337,337,337,337,384,384,433,433,433,433,486,486,541,541,541,541,600,600,661
%N a(n) = Sum_{i=1..n, gcd(6,i)=1} i.
%t Table[Sum[k*KroneckerDelta[GCD[6, k], 1], {k, n}], {n, 80}] (* _Wesley Ivan Hurt_, Jan 20 2024 *)
%Y Cf. A115012.
%K nonn,easy
%O 1,5
%A _N. J. A. Sloane_, Feb 24 2006