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 A047436 #23 Dec 19 2021 04:32:20
%S A047436 5,6,13,14,21,22,29,30,37,38,45,46,53,54,61,62,69,70,77,78,85,86,93,
%T A047436 94,101,102,109,110,117,118,125,126,133,134,141,142,149,150,157,158,
%U A047436 165,166,173,174,181,182,189,190
%N A047436 Numbers that are congruent to {5, 6} mod 8.
%H A047436 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A047436 From _Vincenzo Librandi_, Aug 06 2010: (Start)
%F A047436 a(n) = a(n-1) + a(n-2) - a(n-3).
%F A047436 a(n) = 8*n - a(n-1) - 5, n > 1. (End)
%F A047436 G.f. x*(5+x+2*x^2) / ( (1+x)*(x-1)^2 ). - _R. J. Mathar_, Dec 07 2011
%F A047436 Sum_{n>=1} (-1)^(n+1)/a(n) = (2-sqrt(2))*Pi/16 + log(2)/8 - sqrt(2)*log(sqrt(2)+1)/8. - _Amiram Eldar_, Dec 19 2021
%t A047436 Select[Range[200], MemberQ[{5, 6}, Mod[#, 8]] &] (* _Amiram Eldar_, Dec 19 2021 *)
%Y A047436 Union of A004770 and A017137.
%K A047436 nonn
%O A047436 1,1
%A A047436 _N. J. A. Sloane_