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A108926 Initial members of abundant quintuplets, i.e., values of n such that (n, n+2, n+4, n+6, n+8) are all abundant numbers. 8

%I #13 Mar 06 2022 12:33:52

%S 2988,4728,9724,18844,22984,30544,35148,39948,45048,50464,55788,56808,

%T 58056,58780,69184,78048,81948,85744,101148,106144,108256,109248,

%U 117124,134088,139744,139804,152568,171288,174348,175908,182644,189768,197028

%N Initial members of abundant quintuplets, i.e., values of n such that (n, n+2, n+4, n+6, n+8) are all abundant numbers.

%H Shyam Sunder Gupta, <a href="/A108926/b108926.txt">Table of n, a(n) for n = 1..5000</a>

%t SequencePosition[Table[If[DivisorSigma[1,n]>2n,1,0],{n,200000}],{1,_,1,_,1,_,1,_,1}][[All,1]] (* _Harvey P. Dale_, Mar 06 2022 *)

%o (PARI) is(n)=sigma(n,-1)>2 && sigma(n+2,-1)>2 && sigma(n+4,-1)>2 && sigma(n+6,-1)>2 && sigma(n+8,-1)>2 \\ _Charles R Greathouse IV_, Feb 21 2017

%Y Cf. A005101.

%K nonn

%O 1,1

%A _Jason Earls_, Jul 19 2005

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)