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A048692 Triangle read by rows in which row n contains first n numbers with exactly n distinct prime factors.

%I A048692 #29 Jan 03 2023 14:49:59
%S A048692 2,6,10,30,42,60,210,330,390,420,2310,2730,3570,3990,4290,30030,39270,
%T A048692 43890,46410,51870,53130,510510,570570,690690,746130,870870,881790,
%U A048692 903210,9699690,11741730,13123110,14804790,15825810,16546530,17160990,17687670,223092870,281291010,300690390,340510170,358888530,363993630,380570190,397687290,406816410
%N A048692 Triangle read by rows in which row n contains first n numbers with exactly n distinct prime factors.
%H A048692 David A. Corneth, <a href="/A048692/b048692.txt">Table of n, a(n) for n = 1..10011</a>
%H A048692 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a048/A048692.java">Java program</a> (github)
%e A048692     2;
%e A048692     6,  10;
%e A048692    30,  42,  60;
%e A048692   210, 330, 390, 420;
%e A048692   ...
%t A048692 f[n_] := Flatten[Table[ # [[1]]] & /@ FactorInteger[n]]; (* for n=7 *) Take[ Select[ Range[10^7], Length[f[ # ]] == 7 & ], 7]
%t A048692 Module[{nn=8,dpf=Table[{n,PrimeNu[n]},{n,2 10^7}]},Flatten[Table[Select[dpf,#[[2]]==n&,n],{n,nn}],1][[All,1]]] (* The program generates the first 36 terms of the sequence. *) (* _Harvey P. Dale_, Sep 09 2022 *)
%Y A048692 Cf. A002110 (first column).
%Y A048692 Main diagonal gives A073329.
%Y A048692 Extending the rows to give a square array, we get A125666.
%K A048692 nonn,tabl
%O A048692 1,1
%A A048692 _Amarnath Murthy_, Aug 20 2002
%E A048692 Edited, corrected and extended by _Robert G. Wilson v_, Aug 22 2002
%E A048692 More terms from _David A. Corneth_, Jan 09 2021