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 A081351 #16 Sep 08 2022 08:45:09 %S A081351 1,8,9,24,25,48,49,80,81,120,121,168,169,224,225,288,289,360,361,440, %T A081351 441,528,529,624,625,728,729,840,841,960,961,1088,1089,1224,1225,1368, %U A081351 1369,1520,1521,1680,1681,1848,1849,2024,2025,2208,2209,2400,2401,2600 %N A081351 First row in square maze array of natural numbers A081349. %C A081351 Interleaves the odd squares A016754 with 8 times the triangular numbers A000217. %H A081351 Vincenzo Librandi, <a href="/A081351/b081351.txt">Table of n, a(n) for n = 0..10000</a> %H A081351 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-2,-1,1). %F A081351 a(n) = (n+1)*(n+2)-(n+1)*(-1)^n = 2*C(n+2,2)-C(n+1,1)*(-1)^n. %F A081351 G.f.: (x^3-x^2+7*x+1)/((1-x)^3*(1+x)^2). [_Colin Barker_, Sep 03 2012] %o A081351 (Magma) [(n+1)*(n+2)-(n+1)*(-1)^n: n in [0..50]]; // _Vincenzo Librandi_, Sep 06 2011 %Y A081351 Cf. A081350, A081352. %K A081351 nonn,easy %O A081351 0,2 %A A081351 _Paul Barry_, Mar 19 2003