A038512 Nonprime numbers with smallest prime factor >= 13.

169, 221, 247, 289, 299, 323, 361, 377, 391, 403, 437, 481, 493, 527, 529, 533, 551, 559, 589, 611, 629, 667, 689, 697, 703, 713, 731, 767, 779, 793, 799, 817, 841, 851, 871, 893, 899, 901, 923, 943, 949, 961, 989, 1003, 1007, 1027, 1037, 1073, 1079

Offset: 1

Author

Jeff Burch

Keywords

• nonn

Comments

Composite numbers k such that k^120 mod 2310 = 1. - Gary Detlefs, May 02 2012

The asymptotic density of this sequence is 16/77. - Amiram Eldar, Mar 22 2021

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Intersection of A002808 and A008365.

Programs

Maple

for n from 1 to 1079 do if n^120 mod 2310=1 then print(n) fi od; # Gary Detlefs, May 02 2012

Mathematica

Select[Range[1000], ! PrimeQ[#] && FactorInteger[#][[1, 1]] >= 13 &] (* T. D. Noe, Mar 16 2013 *)

Extensions

913=11*83 deleted by Jean-Marc Rebert, Jul 08 2009

923=13*71 added by Howard Berman (howard_berman(AT)hotmail.com), Jan 22 2010

1 removed by T. D. Noe, Mar 16 2013