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 A195463 #38 Feb 21 2025 11:46:02 %S A195463 11,23,71,263,1031,4103,16391,65543,262151,1048583,4194311,16777223, %T A195463 67108871,268435463,1073741831,4294967303,17179869191,68719476743, %U A195463 274877906951,1099511627783,4398046511111,17592186044423,70368744177671,281474976710663,1125899906842631 %N A195463 a(n) = 4^(n+1) + 7. %C A195463 These are the even terms of A168415. Since the odd terms of A168415 are divisible by three the primes of this sequence are the same as A104066. %H A195463 Vincenzo Librandi, <a href="/A195463/b195463.txt">Table of n, a(n) for n = 0..1000</a> %H A195463 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (5,-4). %F A195463 a(n) = 4^(n+1) + 7. %F A195463 From _Alexander R. Povolotsky_, Sep 19 2011: (Start) %F A195463 G.f.: (11 - 32*x)/(1 - 5*x + 4*x^2). %F A195463 a(n+1) = 4*a(n) - 21. (End) %F A195463 a(n) = A188165(2*n+2) - 2. - _Bruno Berselli_, Sep 26 2011 %F A195463 E.g.f.: exp(x)*(4*exp(3*x) + 7). - _Elmo R. Oliveira_, Feb 20 2025 %t A195463 4^Range[25] + 7 (* _Paolo Xausa_, Feb 21 2025 *) %o A195463 (PARI) a(n)=4^(n+1)+7 \\ _Charles R Greathouse IV_, Sep 19 2011 %o A195463 (Magma) [4^(n+1) + 7: n in [0..30]]; // _Vincenzo Librandi_, Sep 30 2011 %Y A195463 Cf. A104066, A168415, A188165. %K A195463 nonn,easy %O A195463 0,1 %A A195463 _Brad Clardy_, Sep 19 2011