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 A171501 #23 Sep 08 2022 08:45:50 %S A171501 0,1,3,-1,7,-9,23,-41,87,-169,343,-681,1367,-2729,5463,-10921,21847, %T A171501 -43689,87383,-174761,349527,-699049,1398103,-2796201,5592407, %U A171501 -11184809,22369623,-44739241,89478487,-178956969,357913943,-715827881 %N A171501 Inverse binomial transform of A084640. %C A171501 a(n) and differences are %C A171501 0, 1, 3, -1, 7, -9, %C A171501 1, 2, -4, 8, -16, 32, =(-1)^(n+1) * A171449(n), %C A171501 1, -6, 12, -24, 48, -96, %C A171501 -7, 18, -36, 72, -144, 288, %C A171501 25, -54, 108, -216, 432, -864, %C A171501 Vertical: 1) 0 followed with A168589(n). %C A171501 2) (-1 followed with A008776(n) ) signed. See A025192(n). %C A171501 Main diagonal: see A167747(1+n). - _Paul Curtz_, Jun 16 2011 %H A171501 Vincenzo Librandi, <a href="/A171501/b171501.txt">Table of n, a(n) for n = 0..1000</a> %H A171501 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (-1,2). %F A171501 a(n) = A140966(n), n>0. %F A171501 G.f.: x*(1+4*x) / ( (1+2*x)*(1-x) ). - _R. J. Mathar_, Jun 14 2011 %F A171501 a(1+n)= (-1)^(1+n) * A001045(1+n) + 2. - _Paul Curtz_, Jun 16 2011 %t A171501 CoefficientList[Series[x*(1 + 4*x)/((1 + 2*x)*(1 - x)), {x, 0, 30}], x] %t A171501 LinearRecurrence[{-1,2},{0,1,3},40] (* _Harvey P. Dale_, Jan 14 2020 *) %o A171501 (Magma) I:=[0, 1, 3]; [n le 3 select I[n] else -Self(n-1) + 2*Self(n-2): n in [1..40]]; // _Vincenzo Librandi_, Oct 18 2012 %K A171501 easy,sign %O A171501 0,3 %A A171501 _Paul Curtz_, Dec 10 2009 %E A171501 Mathematica program by _Olivier Gérard_, Jul 06 2011