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 A136528 a(n) = the highest possible number of positive divisors of the sum of any two distinct positive divisors of n. 1
 2, 3, 4, 4, 4, 4, 6, 6, 6, 6, 6, 4, 5, 6, 8, 6, 8, 6, 8, 8, 8, 8, 9, 8, 6, 9, 8, 8, 9, 6, 10, 9, 9, 9, 10, 4, 8, 8, 12, 8, 10, 6, 10, 12, 10, 10, 12, 8, 12, 8, 8, 8, 12, 12, 12, 12, 12, 12, 12, 4, 7, 12, 12, 8, 12, 6, 12, 12, 12, 12, 12, 4, 6, 12, 10, 12, 12, 10, 16, 12, 12, 12, 12, 12, 8, 12, 12, 12, 16, 8, 12, 12, 12, 12, 16 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS There are d(n)*(d(n)-1)/2 sums of pairs of distinct positive divisors of n, where d(n) = number of positive divisors of n. LINKS EXAMPLE The positive divisors of 6 are 1,2,3,6. Letting d(m) = the number of positive divisors of m: d(1+2)=2; d(1+3)=3; d(1+6)=2; d(2+3)=2; d(2+6)=4; d(3+6)=3. The maximum of these values is 4, so a(6) = 4. CROSSREFS Cf. A136529. Sequence in context: A064004 A195849 A087827 * A263252 A276334 A225486 Adjacent sequences:  A136525 A136526 A136527 * A136529 A136530 A136531 KEYWORD nonn AUTHOR Leroy Quet, Jan 03 2008 EXTENSIONS More terms from Sean A. Irvine, Feb 28 2011 STATUS approved

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Last modified May 16 17:37 EDT 2022. Contains 353718 sequences. (Running on oeis4.)