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 A038512 #24 Mar 22 2021 05:47:19 %S A038512 169,221,247,289,299,323,361,377,391,403,437,481,493,527,529,533,551, %T A038512 559,589,611,629,667,689,697,703,713,731,767,779,793,799,817,841,851, %U A038512 871,893,899,901,923,943,949,961,989,1003,1007,1027,1037,1073,1079 %N A038512 Nonprime numbers with smallest prime factor >= 13. %C A038512 Composite numbers k such that k^120 mod 2310 = 1. - _Gary Detlefs_, May 02 2012 %C A038512 The asymptotic density of this sequence is 16/77. - _Amiram Eldar_, Mar 22 2021 %H A038512 T. D. Noe, <a href="/A038512/b038512.txt">Table of n, a(n) for n = 1..10000</a> %p A038512 for n from 1 to 1079 do if n^120 mod 2310=1 then print(n) fi od; # _Gary Detlefs_, May 02 2012 %t A038512 Select[Range[1000], ! PrimeQ[#] && FactorInteger[#][[1, 1]] >= 13 &] (* _T. D. Noe_, Mar 16 2013 *) %Y A038512 Intersection of A002808 and A008365. %K A038512 nonn %O A038512 1,1 %A A038512 _Jeff Burch_ %E A038512 913=11*83 deleted by _Jean-Marc Rebert_, Jul 08 2009 %E A038512 923=13*71 added by Howard Berman (howard_berman(AT)hotmail.com), Jan 22 2010 %E A038512 1 removed by _T. D. Noe_, Mar 16 2013