This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A333079 #26 Jan 16 2024 13:52:14
%S A333079 345,1645,6489,8041,23881,88473,115957,342637,3256261,4114285,4646101,
%T A333079 5054221,13384681,17897737,20901553,23807821,42081409,64580041,
%U A333079 65380921,70366153,82175857,110344621,137331565,164109901,286078081,331957897,366611617,367891717,489645157
%N A333079 The largest nontrivial divisor of n equals the sum of the other nontrivial divisors of n.
%C A333079 A divisor of n other than 1 and n is called a nontrivial divisor of n.
%C A333079 In general, if p, p+k, and q = (p^2+(2+k)*p+k)/(k-1) are 3 primes and p < p+k < q, then p(p+k)q is a term. In particular, if p, p+2, and p^2+4*p+2 are 3 primes, then p(p+2)(p^2+4*p+2) is a term. - _Giovanni Resta_, Mar 08 2020
%C A333079 Each term in this sequence has at least eight divisors. - _Bernard Schott_, Mar 09 2020
%e A333079 The nontrivial divisors of 345 are 3, 5, 15, 23, 69, 115, the largest of which, 115, is equal to the sum of the other nontrivial divisors 3, 5, 15, 23, 69.
%t A333079 Select[Range[10^5], 2 # / FactorInteger[#][[1, 1]] == DivisorSigma[1, #] - # - 1 &] (* _Giovanni Resta_, Mar 07 2020 *)
%t A333079 lndQ[n_]:=With[{c=TakeDrop[Rest[Most[Divisors[n]]],-1]},c[[1,1]]==Total[c[[2]]]]; Select[Range[ 51*10^5],lndQ]//Quiet (* The program generates the first 12 terms of the sequence. *) (* _Harvey P. Dale_, Jan 16 2024 *)
%o A333079 (PARI) for(k=2,5*10^7,my(d=divisors(k)); if(#d>2&&d[#d-1]==vecsum(d[2..#d-2]), print1(k,", "))) \\ _Hugo Pfoertner_, Mar 07 2020
%Y A333079 Cf. A032742.
%K A333079 nonn
%O A333079 1,1
%A A333079 _Joseph L. Pe_, Mar 07 2020
%E A333079 More terms from _Giovanni Resta_, Mar 07 2020