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A355848 Irregular triangle read by rows in which row n lists the numbers whose divisors have arithmetic mean n, or 0 if no such number exists.

%I A355848 #27 Sep 15 2022 09:19:59
%S A355848 1,3,5,6,7,0,11,14,15,13,20,21,17,22,30,19,27,0,23,33,35,42,45,39,44,
%T A355848 60,29,38,54,56,31,0,46,51,55,66,70,37,49,57,41,65,68,78,96,43,0,47,
%U A355848 62,69,77,105,0,99,126,53,85,102,110,91,92,132,140,0,59,87,95,114,135,168
%N A355848 Irregular triangle read by rows in which row n lists the numbers whose divisors have arithmetic mean n, or 0 if no such number exists.
%e A355848 Triangle begins:
%e A355848   n=1: 1;
%e A355848   n=2: 3;
%e A355848   n=3: 5, 6;
%e A355848   n=4: 7;
%e A355848   n=5: 0;
%e A355848   n=6: 11, 14, 15;
%e A355848   n=7: 13, 20;
%e A355848   n=8: 21;
%e A355848   n=9: 17, 22, 30;
%e A355848   ...
%t A355848 nmax=30; a={}; For[n=1, n<=nmax, n++, nok=0; For[k=1, k<=n(n+1)/2, k++, If[DivisorSum[k,#&]==n*DivisorSigma[0,k], AppendTo[a,k]; nok=1]]; If[nok==0, AppendTo[a,0]]]; a (* _Stefano Spezia_, Jul 20 2022 *)
%Y A355848 Cf. A162538 (left border).
%Y A355848 Cf. A000005, A000203, A003601, A157847, A324990, A324991.
%K A355848 nonn,tabf
%O A355848 1,2
%A A355848 _Mohammed Yaseen_, Jul 20 2022