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 A047667 #16 Aug 30 2025 15:56:24
%S A047667 3,10,25,52,95,158,245,360,507,690,913,1180,1495,1862,2285,2768,3315,
%T A047667 3930,4617,5380,6223,7150,8165,9272,10475,11778,13185,14700,16327,
%U A047667 18070,19933,21920,24035,26282,28665,31188,33855,36670,39637,42760,46043,49490,53105
%N A047667 Row 3 of array in A047666.
%H A047667 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A047667 a(n) = (n/3)*(2*n^2 + 7).
%F A047667 From _Elmo R. Oliveira_, Aug 26 2025: (Start)
%F A047667 G.f.: x*(3 - 2*x + 3*x^2)/(x - 1)^4.
%F A047667 E.g.f.: x*(9 + 6*x + 2*x^2)*exp(x)/3.
%F A047667 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 4.
%F A047667 a(n) = A192793(n)/36. (End)
%o A047667 (PARI) my(x='x+O('x^44)); Vec(x*(3-2*x+3*x^2)/(x-1)^4) \\ _Elmo R. Oliveira_, Aug 26 2025
%Y A047667 Cf. A047666, A192793.
%K A047667 nonn,easy,changed
%O A047667 1,1
%A A047667 _N. J. A. Sloane_
%E A047667 More terms from _Elmo R. Oliveira_, Aug 26 2025