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 A086445 #23 Sep 08 2022 08:45:11 %S A086445 1,2,4,7,13,24,46,89,175,346,688,1371,2737,5468,10930,21853,43699, %T A086445 87390,174772,349535,699061,1398112,2796214,5592417,11184823,22369634, %U A086445 44739256,89478499,178956985,357913956,715827898,1431655781,2863311547 %N A086445 Partial sums of A005578. %C A086445 With [0,0,0] prepended to it, this is an autosequence of the first kind. - _Jean-François Alcover_, Oct 21 2019 %H A086445 Vincenzo Librandi, <a href="/A086445/b086445.txt">Table of n, a(n) for n = 0..1000</a> %H A086445 OEIS Wiki, <a href="https://oeis.org/wiki/Autosequence">Autosequence</a> %H A086445 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,-1,-3,2). %F A086445 G.f.: (1-x-x^2)/((1+x)(1-x)^2(1-2x)). %F A086445 a(n) = 2*2^n/3+(-1)^n/12+n/2+1/4. %F A086445 a(n) = A000975(n) + A008619(n). %F A086445 a(0) = 1, a(n) = floor(2*a(n-1) - n/2 + 1) for n>0. - _Gerald McGarvey_, Aug 31 2004 %F A086445 a(n+1) - 2*a(n) = -floor(n/2) = -A004526(n). - _Jean-François Alcover_, Oct 21 2019 [noticed by _Paul Curtz_ in a private e-mail] %p A086445 A086445:=n->2*2^n/3+(-1)^n/12+n/2+1/4: seq(A086445(n), n=0..40); # _Wesley Ivan Hurt_, Apr 24 2017 %t A086445 CoefficientList[Series[(1-x-x^2)/((1+x)(1-x)^2(1-2x)),{x,0,40}],x] (* _Vincenzo Librandi_, Apr 05 2012 *) %t A086445 LinearRecurrence[{3,-1,-3,2},{1,2,4,7},40] (* _Harvey P. Dale_, May 28 2015 *) %o A086445 (Magma) [2*2^n/3+(-1)^n/12+n/2+1/4: n in [0..40]]; // _Vincenzo Librandi_, Apr 05 2012 %Y A086445 Cf. A000975, A004526, A005578, A008619. %K A086445 nonn,easy %O A086445 0,2 %A A086445 _Paul Barry_, Jul 20 2003