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A083873
Primitive abundant numbers that set a new record for number of divisors.
2
20, 70, 272, 550, 945, 1575, 3465, 15015, 47025, 81081, 153153, 692835, 1851759, 3633903, 6084351, 22309287, 95009481, 131339637, 277272567, 1321122231, 1516844043, 5391411025, 28816162375, 40342627325, 181667110625, 186096635725, 213239601575
OFFSET
1,1
MATHEMATICA
abQ[n_] := DivisorSigma[-1, n] > 2; defQ[n_] := DivisorSigma[-1, n] < 2; primQ[n_] := abQ[n] && AllTrue[n/FactorInteger[n][[;; , 1]], defQ]; s = {}; dm = 0; Do[If[(d = DivisorSigma[0, n]) > dm && primQ[n], dm = d; AppendTo[s, n]], {n, 1, 10^6}]; s (* Amiram Eldar, Oct 20 2022 *)
CROSSREFS
Sequence in context: A053741 A303609 A052516 * A240820 A143854 A263969
KEYWORD
nonn
AUTHOR
Jason Earls, Jun 18 2003
EXTENSIONS
More terms from Lambert Herrgesell (zero815(AT)googlemail.com), Jan 02 2006
a(20)-a(24) from Donovan Johnson, Apr 09 2010
a(25)-a(27) from Donovan Johnson, Oct 21 2012
STATUS
approved