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 A047473 #41 Dec 18 2021 04:12:27
%S A047473 2,3,10,11,18,19,26,27,34,35,42,43,50,51,58,59,66,67,74,75,82,83,90,
%T A047473 91,98,99,106,107,114,115,122,123,130,131,138,139,146,147,154,155,162,
%U A047473 163,170,171,178,179,186,187,194,195,202,203,210,211,218,219,226,227,234
%N A047473 Numbers that are congruent to {2, 3} mod 8.
%C A047473 Numbers k such that k and k+2 have the same digital binary sum. - _Benoit Cloitre_, Dec 01 2002
%C A047473 Also, numbers k such that k*(3*k + 1)/8 + 1/4 is a nonnegative integer. - _Bruno Berselli_, Feb 14 2017
%H A047473 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A047473 a(n) = 8*n - a(n-1) - 11 for n>1, a(1)=2. - _Vincenzo Librandi_, Aug 06 2010
%F A047473 From _R. J. Mathar_, Oct 08 2011: (Start)
%F A047473 a(n) = 4*n - 7/2 - 3*(-1)^n/2.
%F A047473 G.f.: x*(2 + x + 5*x^2)/((1 + x)*(1 - x)^2). (End)
%F A047473 a(1)=2, a(2)=3, a(3)=10; for n>3, a(n) = a(n-1) + a(n-2) - a(n-3). - _Harvey P. Dale_, Sep 28 2012
%F A047473 Sum_{n>=1} (-1)^(n+1)/a(n) = (2-sqrt(2))*Pi/16 + sqrt(2)*log(sqrt(2)+1)/8 - log(2)/8. - _Amiram Eldar_, Dec 18 2021
%t A047473 Flatten[# + {2,3} &/@ (8 Range[0, 30])] (* or *) LinearRecurrence[{1, 1, -1}, {2, 3, 10}, 60] (* _Harvey P. Dale_, Sep 28 2012 *)
%Y A047473 Union of A017089 and A017101.
%Y A047473 Cf. A047467, A047468, A047470, A047471.
%K A047473 nonn,easy
%O A047473 1,1
%A A047473 _N. J. A. Sloane_
%E A047473 More terms from _Vincenzo Librandi_, Aug 06 2010