# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a139287 Showing 1-1 of 1 %I A139287 #8 Sep 08 2022 08:45:33 %S A139287 7,31,511,8191,2097151,33554431,8589934591,137438953471, %T A139287 35184372088831,144115188075855871,2305843009213693951, %U A139287 9444732965739290427391,2417851639229258349412351,38685626227668133590597631 %N A139287 2^(2p - 1) - 1, where p is prime. %H A139287 Vincenzo Librandi, Table of n, a(n) for n = 1..200 %t A139287 Table[(2^(2 Prime[n] - 1) - 1), {n, 1, 20}] (* _Vincenzo Librandi_, May 24 2014 *) %o A139287 (Magma)[2^(2*p-1)-1: p in PrimesUpTo(200)]; // _Vincenzo Librandi_, Dec 15 2010 %Y A139287 Cf. A000040, A000079, A076274, A139286, A139288, A139289, A139290, A139291, A139292, A139293, A139294, A139306. %K A139287 nonn,easy %O A139287 1,1 %A A139287 _Omar E. Pol_, Apr 13 2008 %E A139287 a(9) corrected by _Vincenzo Librandi_, May 24 2014 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE