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 A191139 #11 Jul 13 2013 12:04:10 %S A191139 1,5,17,53,65,161,197,209,257,485,593,629,641,773,785,833,1025,1457, %T A191139 1781,1889,1925,1937,2321,2357,2369,2501,2513,2561,3077,3089,3137, %U A191139 3329,4097,4373,5345,5669,5777,5813,5825,6965,7073,7109,7121,7505,7541,7553,7685,7697,7745,9233,9269,9281,9413,9425,9473,9989,10001 %N A191139 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+2 and 4x-3 are in a. %C A191139 See A191113. %H A191139 Reinhard Zumkeller, <a href="/A191139/b191139.txt">Table of n, a(n) for n = 1..10000</a> %t A191139 h = 3; i = 2; j = 4; k = -3; f = 1; g = 9; %t A191139 a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191139 *) %t A191139 b = (a - 2)/3; c = (a + 3)/4; r = Range[1, 1500]; %t A191139 d = Intersection[b, r] (* A191143 *) %t A191139 e = Intersection[c, r] (* A191119 *) %o A191139 (Haskell) %o A191139 import Data.Set (singleton, deleteFindMin, insert) %o A191139 a191139 n = a191139_list !! (n-1) %o A191139 a191139_list = 1 : f (singleton 5) %o A191139 where f s = m : (f $ insert (3*m+2) $ insert (4*m-3) s') %o A191139 where (m, s') = deleteFindMin s %o A191139 -- _Reinhard Zumkeller_, Jun 01 2011 %Y A191139 Cf. A191113. %K A191139 nonn %O A191139 1,2 %A A191139 _Clark Kimberling_, May 28 2011