A094702 - OEIS

A094702

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

2, 12, 42, 90, 110, 152, 171, 208, 231, 336, 408, 476, 506, 765, 783, 840, 1242, 1380, 1584, 1911, 2120, 2162, 2528, 2604, 2688, 2706, 2720, 2970, 3162, 3172, 3325, 3392, 3422, 3619, 3654, 3708, 3870, 4144, 4371, 4472, 4508, 4712, 4760, 4876, 5256, 5372

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

COMMENTS

"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.

LINKS

Table of n, a(n) for n=0..45.

EXAMPLE

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.

CROSSREFS

Cf. A000010, A000203, A094701.

Sequence in context: A185619 A048014 A364598 * A001621 A277935 A290928

Adjacent sequences: A094699 A094700 A094701 * A094703 A094704 A094705

KEYWORD

nonn

AUTHOR

Walter Nissen, May 20 2004

STATUS

approved