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%I #19 Mar 21 2019 02:39:05
%S 1,4,7,14,23,41,56,89,119,164,206,281,335,437,518,626,734,902,1019,
%T 1226,1382,1592,1787,2084,2288,2618,2888,3239,3545,4007,4307,4832,
%U 5240,5750,6206,6818,7268,8006,8573,9281,9881,10781,11375,12362
%N Number of colors that can be mixed with n >= 0 units of yellow, blue, red.
%H T. D. Noe, <a href="/A048241/b048241.txt">Table of n, a(n) for n = 0..1000</a>
%F a(n) = number of triples (i, j, k) with 0 <= i+j+k <= n and gcd(i, j, k) = 1.
%F a(n) = A048134(n)+1. - _T. D. Noe_, Jan 16 2007
%e a(2)=7: white, primary and secondary colors (null, Y^1, B^1, R^1, Y^1*B^1, Y^1*R^1, B^1*R^1).
%t Accumulate[ Table[ Sum[ MoebiusMu[n/d]*(d+1)*(d+2)/2, {d, Divisors[n]}], {n, 0, 43}]] + 1 (* _Jean-François Alcover_, Oct 16 2013, after _T. D. Noe_ *)
%Y Cf. A048134, A048240.
%K nonn,easy,nice
%O 0,2
%A _Jurjen N.E. Bos_, _N. J. A. Sloane_, Robin Trew (trew(AT)hcs.harvard.edu)
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