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 A265713 Numbers k such that floor(Sum_{d|k} 1 / sigma(d)) = 3. 9
 110880, 166320, 221760, 277200, 327600, 332640, 360360, 388080, 393120, 415800, 443520, 471240, 480480, 491400, 498960, 526680, 540540, 554400, 556920, 582120, 589680, 600600, 622440, 637560, 655200, 665280, 693000, 720720, 776160, 786240, 803880, 831600 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers k such that A265710(k) = floor(A265708(k) / A069934(k)) = floor(A265709(k) / A265710(k)) = 3. See A265714(n) = the smallest number k such that floor(Sum_{d|k} 1/sigma(d)) = n. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 110880 is a term because floor(Sum_{d|110880} 1/sigma(d)) = floor(22333/7440) = 3. MATHEMATICA Select[Range[10^5, 9*10^5], Floor[Sum[1/DivisorSigma[1, d], {d, Divisors@ #}]] == 3 &] (* Michael De Vlieger, Dec 31 2015 *) PROG (MAGMA) [n: n in [1..1000000] | Floor(&+[1/SumOfDivisors(d): d in Divisors(n)]) eq 3] (PARI) isok(n) = floor(sumdiv(n, d, 1/sigma(d))) == 3; \\ Michel Marcus, Dec 27 2015 CROSSREFS Cf. A069934, A000203, A265708, A265709, A265710, A265711, A265712, A265714, A266227, A266228. Sequence in context: A251191 A206540 A251034 * A114684 A146888 A175535 Adjacent sequences:  A265710 A265711 A265712 * A265714 A265715 A265716 KEYWORD nonn AUTHOR Jaroslav Krizek, Dec 25 2015 STATUS approved

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Last modified May 8 19:28 EDT 2021. Contains 343666 sequences. (Running on oeis4.)