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 A049642 Number of divisors of n does not divide sum of divisors of n. 6
 2, 4, 8, 9, 10, 12, 16, 18, 24, 25, 26, 28, 32, 34, 36, 40, 48, 50, 52, 58, 63, 64, 72, 74, 75, 76, 80, 81, 82, 84, 88, 90, 98, 100, 104, 106, 108, 112, 117, 120, 121, 122, 124, 128, 130, 136, 144, 146, 148, 152, 156, 160, 162, 170, 171, 172, 175 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A054025(a(n)) > 0. [Reinhard Zumkeller, Jan 06 2012] REFERENCES Handbook of Number Theory, D. S. Mitrinovic et al., Kluwer, Section III.51. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 MAPLE with(numtheory); A049642:=proc(q) local a, b, c, i, n; for n from 1 to q do   a:=divisors(n); b:=nops(a); c:=0; for i from 1 to b do c:=c+a[i]; od;   if trunc(c/b)<>c/b then print(n); fi; od; end: A049642(1000); # Paolo P. Lava, Oct 26 2012 MATHEMATICA Select[Range[175], Mod[DivisorSigma[1, #], DivisorSigma[0, #]] > 0 &] (* Jayanta Basu, Mar 28 2013 *) PROG (Haskell) import Data.List (findIndices) a049642 n = a049642_list !! (n-1) a049642_list = map (+ 1) \$ findIndices (> 0) a054025_list -- Reinhard Zumkeller, Jan 06 2012 CROSSREFS Complement of A003601. Cf. A000005, A000203. Sequence in context: A047466 A003485 A072602 * A050907 A100675 A196730 Adjacent sequences:  A049639 A049640 A049641 * A049643 A049644 A049645 KEYWORD nonn,easy AUTHOR STATUS approved

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