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 A132769 #36 Nov 29 2024 21:13:27 %S A132769 0,28,58,90,124,160,198,238,280,324,370,418,468,520,574,630,688,748, %T A132769 810,874,940,1008,1078,1150,1224,1300,1378,1458,1540,1624,1710,1798, %U A132769 1888,1980,2074,2170,2268,2368,2470,2574,2680,2788,2898,3010,3124,3240,3358,3478 %N A132769 a(n) = n*(n + 27). %H A132769 Harvey P. Dale, <a href="/A132769/b132769.txt">Table of n, a(n) for n = 0..1000</a> %H A132769 Felix P. Muga II, <a href="https://www.researchgate.net/publication/267327689_Extending_the_Golden_Ratio_and_the_Binet-de_Moivre_Formula">Extending the Golden Ratio and the Binet-de Moivre Formula</a>, Preprint on ResearchGate, March 2014. %H A132769 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1). %F A132769 a(n) = 2*n + a(n-1) + 26, with a(0)=0. - _Vincenzo Librandi_, Aug 03 2010 %F A132769 a(0)=0, a(1)=28, a(2)=58; for n > 2, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - _Harvey P. Dale_, Oct 14 2012 %F A132769 From _Amiram Eldar_, Jan 16 2021: (Start) %F A132769 Sum_{n>=1} 1/a(n) = H(27)/27 = A001008(27)/A102928(27) = 312536252003/2168462696400, where H(k) is the k-th harmonic number. %F A132769 Sum_{n>=1} (-1)^(n+1)/a(n) = 2*log(2)/27 - 57128792093/2168462696400. (End) %F A132769 From _Elmo R. Oliveira_, Nov 29 2024: (Start) %F A132769 G.f.: 2*x*(14 - 13*x)/(1 - x)^3. %F A132769 E.g.f.: exp(x)*x*(28 + x). %F A132769 a(n) = 2*A132756(n). (End) %t A132769 Table[n(n+27),{n,0,50}] (* or *) LinearRecurrence[{3,-3,1},{0,28,58},50] (* _Harvey P. Dale_, Oct 14 2012 *) %o A132769 (PARI) a(n)=n*(n+27) \\ _Charles R Greathouse IV_, Oct 07 2015 %Y A132769 Cf. A001008, A002378, A005563, A028347, A028552, A028557, A028560, A028563, A028566. %Y A132769 Cf. A028569, A098849, A098850, A098603, A098847, A098848, A102928, A120071, A132759. %Y A132769 Cf. A132760, A132761, A132762, A132763, A132764, A132765, A132766, A132767, A132768. %Y A132769 Cf. A132756. %K A132769 nonn,easy %O A132769 0,2 %A A132769 _Omar E. Pol_, Aug 28 2007