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 A130566 #21 Aug 04 2025 21:14:46
%S A130566 1,48,186,460,915,1596,2548,3816,5445,7480,9966,12948,16471,20580,
%T A130566 25320,30736,36873,43776,51490,60060,69531,79948,91356,103800,117325,
%U A130566 131976,147798,164836,183135,202740,223696,246048,269841,295120,321930,350316,380323,411996
%N A130566 Pyramidal 47-gonal numbers.
%H A130566 Vincenzo Librandi, <a href="/A130566/b130566.txt">Table of n, a(n) for n = 0..1000</a>
%H A130566 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A130566 a(n) = (15*n + 1)*(n + 2)*(n + 1)/2.
%F A130566 G.f.: (1+44*x)/(1-x)^4. - _Colin Barker_, Apr 30 2012
%F A130566 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - _Vincenzo Librandi_, Jun 29 2012
%F A130566 From _Elmo R. Oliveira_, Aug 04 2025: (Start)
%F A130566 E.g.f.: exp(x)*(15*x^3 + 91*x^2 + 94*x + 2)/2.
%F A130566 a(n) = (15*n+1)*A000217(n+1). (End)
%t A130566 CoefficientList[Series[(1+44*x)/(1-x)^4,{x,0,40}],x] (* _Vincenzo Librandi_, Jun 29 2012 *)
%t A130566 LinearRecurrence[{4,-6,4,-1},{1,48,186,460},40] (* _Harvey P. Dale_, Jul 07 2025 *)
%o A130566 (Magma) I:=[1, 48, 186, 460]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..40]]; // _Vincenzo Librandi_, Jun 29 2012
%Y A130566 Cf. A000217.
%K A130566 nonn,easy
%O A130566 0,2
%A A130566 _N. J. A. Sloane_, Oct 06 2007, based on a suggestion from an unknown correspondent in 2004