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 A030626 Numbers with exactly 8 divisors. 26
 24, 30, 40, 42, 54, 56, 66, 70, 78, 88, 102, 104, 105, 110, 114, 128, 130, 135, 136, 138, 152, 154, 165, 170, 174, 182, 184, 186, 189, 190, 195, 222, 230, 231, 232, 238, 246, 248, 250, 255, 258, 266, 273, 282, 285, 286, 290, 296, 297, 310, 318 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Since A119479(8)=7, there are never more than 7 consecutive terms. Runs of 7 consecutive terms start at 171897, 180969, 647385... (subsequence of A049053). - Ivan Neretin, Feb 08 2016 LINKS R. J. Mathar, Table of n, a(n) for n = 1..1000 Jérôme Germoni, Nombres à huit diviseurs, Images des Mathématiques, CNRS, 2017 (in French). Eric Weisstein's World of Mathematics, Divisor Product. FORMULA A000005(a(n))=8. - Juri-Stepan Gerasimov, Oct 10 2009 Union A065036 U A007304 U A092759. - Amarnath Murthy, Apr 21 2001 MAPLE select(numtheory:-tau=8, [\$1..1000]); # Robert Israel, Dec 17 2014 MATHEMATICA f[n_]:=Length[Divisors[n]]==8; Select[Range[400], f] (* Vladimir Joseph Stephan Orlovsky, Dec 14 2009 *) Select[Range[400], DivisorSigma[0, #]== 8 &] (* Vincenzo Librandi, Oct 05 2017 *) PROG (PARI) Vec(select(x->x==8, vector(500, i, numdiv(i)), 1)) \\ Michel Marcus, Dec 17 2014 (MAGMA) [n: n in [1..400] | DivisorSigma(0, n) eq 8]; // Vincenzo Librandi, Oct 05 2017 CROSSREFS Essentially the same as A111398. Sequence in context: A334974 A048945 A111398 * A302571 A335054 A348604 Adjacent sequences:  A030623 A030624 A030625 * A030627 A030628 A030629 KEYWORD nonn AUTHOR STATUS approved

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Last modified July 6 12:26 EDT 2022. Contains 355110 sequences. (Running on oeis4.)