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 A045770 Numbers k such that sigma(k) == 8 (mod k). 26
 1, 10, 49, 56, 368, 836, 11096, 17816, 45356, 77744, 91388, 128768, 254012, 388076, 2087936, 2291936, 13174976, 29465852, 35021696, 45335936, 120888092, 260378492, 381236216, 775397948, 3381872252, 4856970752, 6800228816, 8589344768, 44257207676, 114141404156, 1461083549696, 1471763808896, 2199013818368 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(31) > 10^12. - Donovan Johnson, Mar 01 2012 a(34) > 10^13. - Giovanni Resta, Apr 02 2014 Every number of the form 2^(j-1)*(2^j - 9), where 2^j - 9 is prime, is a term. - Jon E. Schoenfield, Jun 02 2019 LINKS Jud McCranie, Table of n, a(n) for n = 1..35 MATHEMATICA Join[{1}, Select[Range[8000000], Mod[DivisorSigma[1, #], #]==8 &]] (* Vincenzo Librandi, Mar 11 2014 *) PROG (PARI) is(n)=sigma(n)%n==8 || n==1 \\ Charles R Greathouse IV, Mar 09 2014 CROSSREFS Cf. A054024, A045768, A045769, A088834, A076496. Sequence in context: A126734 A264266 A048698 * A217165 A154066 A056578 Adjacent sequences: A045767 A045768 A045769 * A045771 A045772 A045773 KEYWORD nonn AUTHOR Dan Hoey EXTENSIONS Extended by T. D. Noe, Apr 06 2011 Initial term 1 added and a(26)-a(30) from Donovan Johnson, Mar 01 2012 a(31)-a(33) from Giovanni Resta, Apr 02 2014 STATUS approved

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Last modified June 4 03:55 EDT 2023. Contains 363118 sequences. (Running on oeis4.)