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 A231366 Number of numbers whose sum of non-divisors (A024816) is equal to n. 5
 2, 0, 1, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(n) = frequency of values n in A024816(m), where A024816(m) = sum of non-divisors of m = antisigma(m). From Charles R Greathouse IV, Nov 11 2013: (Start) So far all n such that a(n) > 1 correspond to members of A067816: a(0) = 2 from 1, 2; a(9) = 2 from 5, 6; a(36844389) = 2 from 8585, 8586; a(129894940) = 2 from 16119, 16120; a(446591224981504) = 2 from 29886159, 29886160. I checked this, and thus Krizek's conjecture below, up to 4*10^19. (End) LINKS FORMULA Conjecture: max a(n) = 2. a(A231368(n)) >= 1, a(A231369(n)) = 0. a(n) = 0 for such n that A231367(n) = 0, a(n) = 0 if A024816(m) = n has no solution. a(n) >= 1 for such n that A231367(n) = 1, a(n) >= 1 if A024816(m) = n for any m. Conjecture: a(n) = 2 iff n is number from A225775 (0, 9, 36844389, 129894940, 446591224981504, …) EXAMPLE a(9) = 2 because there are two numbers m (5, 6) with antisigma(m) = 9. CROSSREFS Cf. A054973 (number of numbers whose divisors sum to n), A231365, A231368, A231367, A231369, A067816. Sequence in context: A154469 A037273 A285313 * A158924 A025426 A269244 Adjacent sequences:  A231363 A231364 A231365 * A231367 A231368 A231369 KEYWORD nonn AUTHOR Jaroslav Krizek, Nov 09 2013 STATUS approved

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Last modified April 22 10:46 EDT 2019. Contains 322330 sequences. (Running on oeis4.)