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 A244878 #18 Jul 18 2024 12:17:15
%S A244878 1,15,130,760,3355,12043,36935,100135,245870,556580,1177295,2351165,
%T A244878 4469610,8141210,14284170,24247962,39970575,64178685,100639000,
%U A244878 154470030,232524589,343854445,500269705,717006745,1013519780,1414412506,1950527645,2660213675,3590789540,4800229700
%N A244878 Number of 6 X 6 traceless symmetric magic squares with magic sum n.
%H A244878 Colin Barker, <a href="/A244878/b244878.txt">Table of n, a(n) for n = 0..1000</a>
%H A244878 R. P. Stanley, <a href="/A002721/a002721.pdf">Examples of Magic Labelings</a>, Unpublished Notes, 1973 [Cached copy, with permission]
%H A244878 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (9,-35,75,-90,42,42,-90,75,-35,9,-1).
%F A244878 G.f.: (1 + 6*x + 30*x^2 + 40*x^3 + 30*x^4 + 6*x^5 + x^6) / ((1 - x)^10*(1 + x)).
%F A244878 a(n) = (945*(507+5*(-1)^n) + 1480896*n + 2062800*n^2 + 1747040*n^3 + 989100*n^4 + 383628*n^5 + 100800*n^6 + 17160*n^7 + 1710*n^8 + 76*n^9) / 483840. - _Colin Barker_, Jan 12 2017
%t A244878 LinearRecurrence[{9,-35,75,-90,42,42,-90,75,-35,9,-1},{1,15,130,760,3355,12043,36935,100135,245870,556580,1177295},30] (* _Harvey P. Dale_, Jul 18 2024 *)
%o A244878 (PARI) Vec((1 + 6*x + 30*x^2 + 40*x^3 + 30*x^4 + 6*x^5 + x^6) / ((1 - x)^10*(1 + x)) + O(x^30)) \\ _Colin Barker_, Jan 12 2017
%Y A244878 Row n=6 of A333351.
%K A244878 nonn,easy
%O A244878 0,2
%A A244878 _N. J. A. Sloane_, Jul 08 2014