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 A027970 #20 Mar 24 2025 22:34:58
%S A027970 1,4,11,29,76,196,487,1148,2552,5353,10636,20120,36425,63415,106630,
%T A027970 173821,275603,426242,644593,955207,1389626,1987886,2800249,3889186,
%U A027970 5331634,7221551,9672794,12822346,16833919,21901961,28256096
%N A027970 a(n) = T(n, 2*n-8), T given by A027960.
%H A027970 Colin Barker, <a href="/A027970/b027970.txt">Table of n, a(n) for n = 4..1000</a>
%H A027970 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (9,-36,84,-126,126,-84,36,-9,1).
%F A027970 Sequence satisfies an 8-degree polynomial approximating A002878.
%F A027970 a(n) = (-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320. - _Colin Barker_, Nov 25 2014
%F A027970 G.f.: x^4*(x^8-5*x^7+11*x^6-10*x^5-x^4+10*x^3-11*x^2+5*x-1) / (x-1)^9. - _Colin Barker_, Nov 25 2014
%F A027970 From _G. C. Greubel_, Jul 01 2019: (Start)
%F A027970 a(n) = A027971(n+1) - A027971(n).
%F A027970 E.g.f.: (1169280 + 443520*x + 80640*x^2 + 6720*x^3 +(-1169280 +725760*x -221760*x^2 +47040*x^3 -6720*x^4 +1008*x^5 -56*x^6 +16*x^7 +x^8)*exp(x) )/8!. (End)
%t A027970 Table[(-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320, {n, 4, 40}] (* _G. C. Greubel_, Jul 01 2019 *)
%o A027970 (PARI) Vec(x^4*(x^8-5*x^7+11*x^6-10*x^5-x^4+10*x^3-11*x^2+5*x-1)/(x-1)^9 + O(x^40)) \\ _Colin Barker_, Nov 25 2014
%o A027970 (PARI) for(n=4,40, print1((-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320, ", ")) \\ _G. C. Greubel_, Jul 01 2019
%o A027970 (Magma) [(-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320: n in [4..40]]; // _G. C. Greubel_, Jul 01 2019
%o A027970 (Sage) [(-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320 for n in (4..40)] # _G. C. Greubel_, Jul 01 2019
%o A027970 (GAP) List([4..40], n-> (-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320); # _G. C. Greubel_, Jul 01 2019
%Y A027970 A column of triangle A026998.
%K A027970 nonn,easy
%O A027970 4,2
%A A027970 _Clark Kimberling_