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 A222408 #17 Aug 22 2025 17:57:40
%S A222408 1,11,61,211,551,1201,2311,4061,6661,10351,15401,22111,30811,41861,
%T A222408 55651,72601,93161,117811,147061,181451,221551,267961,321311,382261,
%U A222408 451501,529751,617761,716311,826211,948301,1083451
%N A222408 Partial sums of A008531, or crystal ball sequence for {A_4}* lattice.
%H A222408 Ben Thurston, <a href="/A222408/a222408.png">2-dimensional model of initial terms (cf. A001846)</a>
%H A222408 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A222408 a(n) = (4+10*n+15*n^2+10*n^3+5*n^4)/4. G.f.: -(x^4+6*x^3+16*x^2+6*x+1) / (x-1)^5. [_Colin Barker_, Mar 08 2013]
%t A222408 LinearRecurrence[{5,-10,10,-5,1},{1,11,61,211,551},40] (* _Harvey P. Dale_, Aug 22 2025 *)
%o A222408 (PARI) a(n)=5*n*(n+1)*(n^2+n+2)/4 \\ _Charles R Greathouse IV_, Mar 08 2013
%Y A222408 Cf. A008531, A001846.
%K A222408 nonn,easy,changed
%O A222408 0,2
%A A222408 _N. J. A. Sloane_, Feb 21 2013