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 A176634 #11 Jun 20 2023 14:23:17 %S A176634 89,519,2063,8223,32831,131199,524543,2097663,8389631,33556479, %T A176634 134221823,536879103,2147500031,8589967359,34359803903,137439084543, %U A176634 549756076031,2199023779839,8796094070783,35184374185983 %N A176634 a(n) = 6*a(n-1)-8*a(n-2)-3 for n > 2; a(0) = 89, a(1) = 519, a(2) = 2063. %C A176634 Related to Reverse and Add trajectory of 77 in base 2: a(n)= A075253(4*n+2)/3, i.e., one third of third quadrisection of A075253. %H A176634 Vincenzo Librandi, <a href="/A176634/b176634.txt">Table of n, a(n) for n = 0..1000</a> %H A176634 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8). %F A176634 a(n) = 128*4^n+4*2^n-1 for n > 0, a(1) = 89. %F A176634 G.f.: (89-104*x-324*x^2+336*x^3)/((1-x)*(1-2*x)*(1-4*x)). %F A176634 G.f. for the sequence starting at a(1): x*(519-1570*x+1048*x^2)/((1-x)* (1-2*x)*(1-4*x)). %t A176634 CoefficientList[Series[(89 - 104 x - 324 x^2 + 336 x^3)/((1 - x) (1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* _Vincenzo Librandi_, Sep 24 2013 *) %t A176634 LinearRecurrence[{7,-14,8},{89,519,2063,8223},20] (* _Harvey P. Dale_, Jun 20 2023 *) %o A176634 (PARI) {m=20; v=concat([89, 519, 2063], vector(m-3)); for(n=4, m, v[n]=6*v[n-1]-8*v[n-2]-3); v} %o A176634 (Magma) [89] cat [128*4^n+4*2^n-1: n in [1..25]]; // _Vincenzo Librandi_, Sep 24 2013 %Y A176634 Cf. A075253 (Reverse and Add trajectory of 77 in base 2), A176632, A176633, A176635. %K A176634 nonn %O A176634 0,1 %A A176634 _Klaus Brockhaus_, Apr 22 2010