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 A138129 #10 Jun 23 2025 14:30:52 %S A138129 0,1729,3458,5187,6916,8645,10374,12103,13832,15561,17290,19019,20748, %T A138129 22477,24206,25935,27664,29393,31122,32851,34580,36309,38038,39767, %U A138129 41496,43225,44954,46683,48412,50141,51870,53599,55328,57057,58786,60515,62244,63973,65702,67431 %N A138129 Multiples of 1729, the Hardy-Ramanujan number. %C A138129 About 1729: "No," said Ramanujan, "It is a very interesting number..." %D A138129 David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1997, p. 153. %H A138129 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A138129 a(n) = 1729*n. %F A138129 From _Elmo R. Oliveira_, Jun 23 2025: (Start) %F A138129 G.f.: 1729*x/(1-x)^2. %F A138129 E.g.f.: 1729*x*exp(x). %F A138129 a(n) = 91*A008601(n). %F A138129 a(n) = 2*a(n-1) - a(n-2). (End) %t A138129 1729Range[0, 37] (* _Alonso del Arte_, Feb 19 2015 *) %o A138129 (PARI) a(n)=1729*n \\ _Charles R Greathouse IV_, Feb 21 2015 %o A138129 (PARI) concat(0, Vec(1729*x/(1-x)^2 + O(x^40))) \\ _Elmo R. Oliveira_, Jun 23 2025 %Y A138129 Cf. A001235, A011541, A133019, A133029, A138130. %Y A138129 Cf. A008601. %K A138129 easy,nonn %O A138129 0,2 %A A138129 _Omar E. Pol_, Mar 09 2008 %E A138129 More terms from _Elmo R. Oliveira_, Jun 23 2025