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 A047463 #27 Feb 21 2025 23:48:42
%S A047463 2,4,10,12,18,20,26,28,34,36,42,44,50,52,58,60,66,68,74,76,82,84,90,
%T A047463 92,98,100,106,108,114,116,122,124,130,132,138,140,146,148,154,156,
%U A047463 162,164,170,172,178,180,186,188,194,196,202,204,210,212,218,220,226,228,234
%N A047463 Numbers that are congruent to {2, 4} mod 8.
%C A047463 First differences in A010696.
%H A047463 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A047463 a(n) = 8*n - a(n-1) - 10, with a(1)=2. - _Vincenzo Librandi_, Aug 06 2010
%F A047463 From _Bruno Berselli_, May 11 2011: (Start)
%F A047463 G.f.: 2*x*(1+x+2*x^2)/((1+x)*(1-x)^2).
%F A047463 a(n) = 4*n-(-1)^n-3.
%F A047463 Sum_{i=1..n} a(i) = 2*A014848(n).
%F A047463 a(n) = 2*A042963(n-1). (End)
%F A047463 Sum_{n>=1} (-1)^(n+1)/a(n) = Pi/16 + log(2)/8. - _Amiram Eldar_, Dec 18 2021
%t A047463 Select[Range[250], MemberQ[{2, 4}, Mod[#, 8]] &] (* _Amiram Eldar_, Dec 18 2021 *)
%o A047463 (Magma) [ n: n in [2..234 by 2] | n mod 8 in [2,4] ]; // _Bruno Berselli_, May 11 2011
%Y A047463 Union of A017089 and A017113.
%Y A047463 Cf. A014848.
%K A047463 nonn,easy
%O A047463 1,1
%A A047463 _N. J. A. Sloane_
%E A047463 More terms from _Vincenzo Librandi_, Aug 06 2010