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 A097870 #22 Sep 08 2022 08:45:14
%S A097870 1,2,4,10,17,27,45,66,92,130,173,223,289,362,444,546,657,779,925,1082,
%T A097870 1252,1450,1661,1887,2145,2418,2708,3034,3377,3739,4141,4562,5004,
%U A097870 5490,5997,6527,7105,7706,8332,9010,9713,10443,11229,12042,12884,13786,14717,15679
%N A097870 Molien series for group of order 4608 acting on joint weight enumerators of a pair of binary doubly-even self-dual codes.
%C A097870 This is the Molien series for the group of order 128 discussed in A097869 extended by the extra generator diag{1,1,i,i}. This group was not considered in the reference cited.
%C A097870 The first g.f. inserts zeros between each pair of terms; the second g.f. does not. - _Colin Barker_, Feb 12 2015
%H A097870 Colin Barker, <a href="/A097870/b097870.txt">Table of n, a(n) for n = 0..1000</a>
%H A097870 F. J. MacWilliams, C. L. Mallows and N. J. A. Sloane, <a href="http://neilsloane.com/doc/gleason2.html">Generalizations of Gleason's theorem on weight enumerators of self-dual codes</a>, IEEE Trans. Inform. Theory, 18 (1972), 794-805.
%H A097870 <a href="/index/Mo#Molien">Index entries for Molien series</a>
%H A097870 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,2,-4,2,-1,2,-1).
%F A097870 G.f.: (1 + x^2 + 2*x^3 + x^4 + x^5 + x^6 + x^7)/(1 - 2*x + x^2 - 2*x^3 +
%F A097870 4*x^4 - 2*x^5 + x^6 - 2*x^7 + x^8).
%F A097870 G.f.: (1+x)*(1-x+x^2)*(1+x^2+x^3+x^4) / ((1-x)^4*(1+x+x^2)^2). - _Colin Barker_, Feb 12 2015
%p A097870 m:=50; S:=series((1+x^3)*(1+x^2+x^3+x^4)/((1-x)*(1-x^3))^2, x, m+1): seq(coeff(S, x, j), j=0..m); # _G. C. Greubel_, Feb 05 2020
%t A097870 CoefficientList[Series[(1+x^3)*(1+x^2+x^3+x^4)/((1-x)*(1-x^3))^2, {x,0,50}], x] (* _G. C. Greubel_, Feb 05 2020 *)
%t A097870 LinearRecurrence[{2,-1,2,-4,2,-1,2,-1},{1,2,4,10,17,27,45,66},50] (* _Harvey P. Dale_, Jun 11 2022 *)
%o A097870 (PARI) Vec((x+1)*(x^2-x+1)*(x^4+x^3+x^2+1)/((x-1)^4*(x^2+x+1)^2) + O(x^100)) \\ _Colin Barker_, Feb 12 2015
%o A097870 (Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( (1+x^3)*(1+x^2+x^3+x^4)/((1-x)*(1-x^3))^2 )); // _G. C. Greubel_, Feb 05 2020
%o A097870 (Sage)
%o A097870 def A097870_list(prec):
%o A097870 P.<x> = PowerSeriesRing(ZZ, prec)
%o A097870 return P( (1+x^3)*(1+x^2+x^3+x^4)/((1-x)*(1-x^3))^2 ).list()
%o A097870 A097870_list(50) # _G. C. Greubel_, Feb 05 2020
%Y A097870 Cf. A097869.
%K A097870 nonn,easy
%O A097870 0,2
%A A097870 _N. J. A. Sloane_, Sep 02 2004