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 A054903 Composite numbers n such that sigma(n)+6 = sigma(n+6), where sigma=A000203. 4
 104, 147, 596, 1415, 4850, 5337, 370047, 1630622, 35020303, 120221396, 3954451796, 742514284703 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Complement of A023201 with respect to A015914. Intersection of A015914 and A018252. Below 1000000 there are only 7 such composite numbers, compared with more than 16000 primes. a(13) > 10^13. - Giovanni Resta, Jul 11 2013 REFERENCES J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 104, p. 37, Ellipses, Paris 2008. LINKS EXAMPLE n=104, sigma(104)+6 = 210+6 = 216 = sigma(104+6) = sigma(110). a(4) = 1415 = 5*283, 1415+6 = 1421 = 7*7*29: sigma(1415) = 1+5+283+1415 = 1704, sigma(1421) = 1+7+29+49+203+1421 = 1710 = sigma(1415)+6. PROG (PARI) forcomposite(n=9, 1e7, if(sigma(n)+6==sigma(n+6), print1(n", "))) \\ Charles R Greathouse IV, Feb 14 2013 CROSSREFS Cf. A015913-A015917, A023200-A023203, A046133, A001359, A054799. Sequence in context: A297912 A253700 A260922 * A074228 A298505 A253693 Adjacent sequences:  A054900 A054901 A054902 * A054904 A054905 A054906 KEYWORD nonn,more AUTHOR Labos Elemer, May 23 2000 EXTENSIONS More terms from Jud McCranie, May 25 2000 New definition from Reinhard Zumkeller, Jan 27 2009 Edited by N. J. A. Sloane, Jan 31 2009 at the suggestion of R. J. Mathar. a(12) from Giovanni Resta, Jul 11 2013 STATUS approved

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Last modified February 18 03:40 EST 2020. Contains 332006 sequences. (Running on oeis4.)