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 A305559 #37 May 28 2025 10:51:19 %S A305559 0,-1,-1,0,1,4,9,16,25,36,49,64,81,100,121,144,169,196,225,256,289, %T A305559 324,361,400,441,484,529,576,625,676,729,784,841,900,961,1024,1089, %U A305559 1156,1225,1296,1369,1444,1521,1600,1681,1764,1849,1936,2025,2116,2209,2304,2401,2500 %N A305559 [0, -1, -1] together with A000290. %C A305559 Squares leading to an autosequence of the first kind. %C A305559 The third sequence of the array %C A305559 A060576(n+1)= 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... %C A305559 A289207(n)= 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, ... %C A305559 a(n)= 0, -1, -1, 0, 1, 4, 9, 16, 25, 36, ... %C A305559 0, 10, 10, 5, 0, 1, 8, 27, 64, 125, ... %C A305559 0, -113, -113, -68, -23, 0, 1, 16, 81, 256, ... . %C A305559 The first full vertical is (-1)^n*A033312(n). %C A305559 From 0, the first two nonzero antidiagonals are 0, -1, 10, -113, 1526, ... = (-1)^n* A176824(n+1). %C A305559 See OEIS Wiki, Autosequence. %C A305559 a(n) difference table: %C A305559 0, -1, -1, 0, 1, 4, 9, 16, 25, ... %C A305559 -1, 0, 1, 1, 3, 5, 7, 9, 11, ... %C A305559 1, 1, 0, 2, 2, 2, 2, 2, 2, ... %C A305559 0, -1, 2, 0, 0, 0, 0, 0, 0, ... %H A305559 Paolo Xausa, <a href="/A305559/b305559.txt">Table of n, a(n) for n = 0..1000</a> %H A305559 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1). %F A305559 From _Stefano Spezia_, May 28 2025: (Start) %F A305559 G.f.: x*(1 - 2*x + x^3 - 2*x^4)/(1 - x)^3. %F A305559 E.g.f.: 9 + 5*x + x^2 - exp(x)*(9 - 5*x + x^2). (End) %t A305559 Join[{0,-1,-1},Range[0,100]^2] (* _Paolo Xausa_, Nov 13 2023 *) %Y A305559 Cf. A003992, A033312, A060576, A176824, A289207, A000290, A113679. %K A305559 sign,easy,less %O A305559 0,6 %A A305559 _Paul Curtz_, Jun 21 2018