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 A126284 #51 Dec 11 2022 02:14:48 %S A126284 1,7,23,59,135,291,607,1243,2519,5075,10191,20427,40903,81859,163775, %T A126284 327611,655287,1310643,2621359,5242795,10485671,20971427,41942943, %U A126284 83885979,167772055,335544211,671088527,1342177163,2684354439 %N A126284 a(n) = 5*2^n - 4*n - 5. %C A126284 Row sums of A125233. %C A126284 A triangle with left and right borders being the odd numbers 1,3,5,7,... will give the same partial sums for the sum of its rows. - _J. M. Bergot_, Sep 29 2012 %C A126284 The triangle in the above comment is constructed the same way as Pascal's triangle, i.e., C(n, k) = C(n-1, k) + C(n-1, k-1). - _Michael B. Porter_, Oct 03 2012 %H A126284 Vincenzo Librandi, <a href="/A126284/b126284.txt">Table of n, a(n) for n = 1..1000</a> %H A126284 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2). %F A126284 a(1) = 1; a(2) = 7; a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3), n > 2. %F A126284 The 6th diagonal from the right of A126277. %F A126284 G.f.: x*(1+3*x)/(1-4*x+5*x^2-2*x^3). - _Colin Barker_, Feb 12 2012 %F A126284 E.g.f.: 5*exp(2*x) - (5+4*x)*exp(x). - _G. C. Greubel_, Oct 23 2018 %p A126284 A126284:=n->5*2^n-4*n-5; seq(A126284(n), n=1..50); # _Wesley Ivan Hurt_, Mar 27 2014 %t A126284 CoefficientList[Series[(1 + 3 x)/(1 - 4 x + 5 x^2 - 2 x^3), {x, 0, 50}], x] (* _Vincenzo Librandi_, Mar 28 2014 *) %o A126284 (PARI) a(n)=5<<n-4*n-5 \\ _Charles R Greathouse IV_, Oct 03 2012 %o A126284 (Magma) [5*2^n - 4*n - 5: n in [1..30]]; // _G. C. Greubel_, Oct 23 2018 %o A126284 (GAP) List([1..30],n->5*2^n-4*n-5); # _Muniru A Asiru_, Oct 24 2018 %Y A126284 Cf. A000384, A125233, A126277. %K A126284 nonn,easy %O A126284 1,2 %A A126284 _Gary W. Adamson_, Dec 24 2006 %E A126284 More terms from _Vladimir Joseph Stephan Orlovsky_, Oct 18 2008 %E A126284 New definition from _R. J. Mathar_, Sep 29 2012