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 A153795 #28 Oct 05 2024 14:38:31
%S A153795 0,5,40,105,200,325,480,665,880,1125,1400,1705,2040,2405,2800,3225,
%T A153795 3680,4165,4680,5225,5800,6405,7040,7705,8400,9125,9880,10665,11480,
%U A153795 12325,13200,14105,15040,16005,17000,18025,19080,20165,21280
%N A153795 5 times octagonal numbers: a(n) = 5*n*(3*n-2).
%H A153795 G. C. Greubel, <a href="/A153795/b153795.txt">Table of n, a(n) for n = 0..1000</a>
%H A153795 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A153795 a(n) = 15*n^2 - 10*n = A000567(n)*5.
%F A153795 a(n) = 30*n + a(n-1) - 25 for n > 0, a(0) = 0. - _Vincenzo Librandi_, Aug 03 2010
%F A153795 From _G. C. Greubel_, Aug 29 2016: (Start)
%F A153795 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
%F A153795 G.f.: 5*x*(1 + 5*x)/(1 - x)^3.
%F A153795 E.g.f.: 5*x*(1 + 3*x)*exp(x). (End)
%t A153795 Table[5 * n * (3 * n - 2) , {n, 0, 25}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 5, 40}, 25] (* _G. C. Greubel_, Aug 28 2016 *)
%o A153795 (PARI) a(n)=5*n*(3*n-2) \\ _Charles R Greathouse IV_, Jun 17 2017
%Y A153795 Cf. A000567, A153794, A153796.
%K A153795 nonn,easy
%O A153795 0,2
%A A153795 _Omar E. Pol_, Jan 20 2009