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Least linear combinations of phi(n) and sigma(n) are multiple.
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%I #10 Mar 05 2015 14:34:21

%S 2,12,42,90,110,152,171,208,231,336,408,476,506,765,783,840,1242,1380,

%T 1584,1911,2120,2162,2528,2604,2688,2706,2720,2970,3162,3172,3325,

%U 3392,3422,3619,3654,3708,3870,4144,4371,4472,4508,4712,4760,4876,5256,5372

%N Least linear combinations of phi(n) and sigma(n) are multiple.

%C "Multiple" is used here with two distinct meanings. The linear combination of phi and sigma must be a multiple of the argument to be tallied (Cf. A094701). There must be a multiple, i.e. at least 2, of those linear combinations for the value to be in this sequence. 3 is not in this sequence because there is only one linear combination with minimal sum, 2, viz., 1*phi(3) + 1*sigma(3), which is a multiple of 3.

%e 2 is in the sequence because there are 3 minimal combinations of phi(2) and sigma(2), viz., 2*sigma(2), 1*phi(2) + 1*sigma(2) and 2*phi(2), all of which are multiples of 2 and all of which have coefficients totaling 2, viz., 0+2 = 1+1 = 2+0.

%Y Cf. A000010, A000203, A094701.

%K nonn

%O 0,1

%A _Walter Nissen_, May 20 2004