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 A061600 #64 Aug 17 2024 18:55:28 %S A061600 1,1,7,25,61,121,211,337,505,721,991,1321,1717,2185,2731,3361,4081, %T A061600 4897,5815,6841,7981,9241,10627,12145,13801,15601,17551,19657,21925, %U A061600 24361,26971,29761,32737,35905,39271,42841,46621,50617,54835,59281,63961 %N A061600 a(n) = n^3 - n + 1. %C A061600 Smallest of n consecutive odd numbers whose sum is n^4. (n^k can be expressed as the sum of n consecutive odd numbers the smallest of which is given by n^(k-1)-n+1.) %D A061600 T. A. Gulliver, Sequences from Cubes of Integers, Int. Math. Journal, 4 (2003), 439-445. %H A061600 Harry J. Smith, <a href="/A061600/b061600.txt">Table of n, a(n) for n = 0..1000</a> %H A061600 Leo Tavares, <a href="/A061600/a061600.jpg">Illustration: Diamond Chains</a> %H A061600 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1). %F A061600 G.f.: (1-3*x+9*x^2-x^3)/(1 - x)^4. a(-n) = -A126420(n). - _Bruno Berselli_, Aug 29 2011 %F A061600 a(n) = 1 + Sum_{k=1..n} 3*(k-1)*k. - _Luce ETIENNE_ and _Michel Marcus_, Nov 01 2014 %F A061600 E.g.f.: exp(x)*(1 + 3*x^2 + x^3). - _Nikolaos Pantelidis_, Feb 13 2023 %e A061600 a(5) = 121 = 5^3 - 5 + 1. We have 121 + 123 + 125 + 127 + 129 = 625 = 5^4. %t A061600 Table[n^3 - n + 1, {n, 0, 40}] (* _Vladimir Joseph Stephan Orlovsky_, Feb 20 2012 *) %t A061600 LinearRecurrence[{4,-6,4,-1},{1,1,7,25},50] (* _Harvey P. Dale_, Aug 17 2020 *) %o A061600 (PARI) a(n) = n^3 - n + 1; \\ _Harry J. Smith_, Jul 25 2009 %o A061600 (Magma) [n^3 - n + 1: n in [0..40]]; // _Vincenzo Librandi_, Aug 29 2011 %Y A061600 Cf. A126420. %K A061600 nonn,easy %O A061600 0,3 %A A061600 _Amarnath Murthy_, May 19 2001 %E A061600 Offset changed from 1 to 0 by _Harry J. Smith_, Jul 25 2009