cp's OEIS Frontend

A258095 Numbers m, such that the smallest prime factor of 1+78557*2^m doesn't belong to the covering set {3, 5, 7, 13, 19, 37, 73}.

%I A258095 #4 May 19 2015 19:01:20
%S A258095 39,183,219,1047,1227,1299,1875,2271,2559,2703,3315,3531,3819,4359,
%T A258095 5079,5187,5403,6015,6339,6447,6843,7491,7599,7671,8499,8535,8859,
%U A258095 9327,9579,10119,10155,10623,10983,11379,11667,11811,12639,12711,13467,13755,13899
%N A258095 Numbers m, such that the smallest prime factor of 1+78557*2^m doesn't belong to the covering set {3, 5, 7, 13, 19, 37, 73}.
%C A258095 A258091(a(n)) < 73, as each term in A258073 has at least one prime factor in the covering set.
%H A258095 Reinhard Zumkeller, <a href="/A258095/b258095.txt">Table of n, a(n) for n = 1..250</a>
%H A258095 Wikipedia, <a href="http://en.wikipedia.org/wiki/Sierpinski_number">Sierpinski Number</a>
%H A258095 Wikipedia, <a href="http://en.wikipedia.org/wiki/Covering_set">Covering set</a>
%e A258095 a(1) = 39; A258073(39) = 43187167471599617 = 71 * 73 * 211 * 39490356709, and 71 is not an element of the covering set.
%o A258095 (Haskell)
%o A258095 a258095 n = a258095_list !! (n-1)
%o A258095 a258095_list = filter
%o A258095                (\x -> a258091 x `notElem` [3, 5, 7, 13, 19, 37, 73]) [1..]
%Y A258095 Cf. A258073, A258091, A020639.
%K A258095 nonn
%O A258095 1,1
%A A258095 _Reinhard Zumkeller_, May 19 2015