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 A249108 Composite numbers whose sum of aliquot parts divides the sum of aliquot parts of the numbers less than or equal to n and relatively prime to n. 2
 133, 667, 961, 1007, 2013, 3986, 5662, 15979, 17453, 33233, 46943, 51101, 94870, 101444, 119045, 134298, 136957, 179567, 188897, 213511, 226203, 246149, 279749, 299139, 306667, 310157, 434531, 449087, 449183, 518459, 519203 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Ray Chandler, Table of n, a(n) for n = 1..40 EXAMPLE Numbers coprime to 133 are 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 20, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 36, 37, 39, 40, 41, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 58, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 78, 79, 80, 81, 82, 83, 85, 86, 87, 88, 89, 90, 92, 93, 94, 96, 97, 99, 100, 101, 102, 103, 104, 106, 107, 108, 109, 110, 111, 113, 115, 116, 117, 118, 120, 121, 122, 123, 124, 125, 127, 128, 129, 130, 131, 132. The sum of their aliquot parts is 4401; sigma(133) - 133 = 27 and 4401 / 27 = 163. MAPLE with(numtheory): P:=proc(q) local a, k, n; for n from 2 to q do if not isprime(n) then a:=0; for k from 1 to n do if gcd(k, n)=1 then a:=a+sigma(k)-k; fi; od; if type(a/(sigma(n)-n), integer) then print(n); fi; fi; od; end: P(10^9); PROG (PARI) lista(nn) = {forcomposite(n=1, nn, s = 0; for (i=1, n, if (gcd(n, i) == 1, s += sigma(i)-i); ); if ((s % (sigma(n)-n)) == 0, print1(n, ", ")); ); } \\ Michel Marcus, Nov 07 2014 CROSSREFS Cf. A001065, A249109, A249396, A249397. Sequence in context: A267288 A334037 A137879 * A020237 A217690 A117565 Adjacent sequences:  A249105 A249106 A249107 * A249109 A249110 A249111 KEYWORD nonn AUTHOR Paolo P. Lava, Oct 21 2014 EXTENSIONS a(10)-a(13) from Michel Marcus, Nov 07 2014 a(14)-a(31) from Ray Chandler, Nov 12 2014 STATUS approved

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Last modified August 10 19:52 EDT 2020. Contains 336381 sequences. (Running on oeis4.)