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 A138130 #25 Jun 23 2025 14:31:00 %S A138130 1,1729,2989441,5168743489,8936757492481,15451653704499649, %T A138130 26715909255079893121,46191807102033135206209, %U A138130 79865634479415290771535361,138087682014909037743984639169,238753602203777726259349441123201,412804978210331688702415183702014529 %N A138130 Powers of 1729, the Hardy-Ramanujan number. %C A138130 About 1729: "No," said Ramanujan, "It is a very interesting number..." %D A138130 David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1997, p. 153. %H A138130 Wikipedia, <a href="https://en.wikipedia.org/wiki/1729_(number)">1729 (number)</a>. %H A138130 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1729). %F A138130 a(n) = 1729^n. %F A138130 From _Chai Wah Wu_, Jan 19 2021: (Start) %F A138130 a(n) = 1729*a(n-1) for n > 0. %F A138130 G.f.: 1/(1 - 1729*x). (End) %F A138130 From _Elmo R. Oliveira_, Jun 23 2025: (Start) %F A138130 E.g.f.: exp(1729*x). %F A138130 a(n) = A000420(n)*A001022(n)*A001029(n). (End) %t A138130 1729^Range[0, 9] (* _Alonso del Arte_, Oct 18 2014 *) %o A138130 (PARI) a(n)=1729^n \\ _Charles R Greathouse IV_, Jan 20 2014 %Y A138130 Cf. A001235, A011541, A133019, A133029, A138129. %Y A138130 Cf. A000420, A001022, A001029. %K A138130 nonn,easy %O A138130 0,2 %A A138130 _Omar E. Pol_, Mar 09 2008