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 A130876 #18 Jul 09 2025 04:27:23
%S A130876 1,1730,5188,10375,17291,25936,36310,48413,62245,77806,95096,114115,
%T A130876 134863,157340,181546,207481,235145,264538,295660,328511,363091,
%U A130876 399400,437438,477205,518701,561926,606880,653563,701975,752116,803986,857585,912913
%N A130876 Centered 1729-gonal numbers.
%H A130876 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A130876 a(n) = 1 + (1729/2)*n + (1729/2)*n^2.
%F A130876 From _Elmo R. Oliveira_, Nov 27 2024: (Start)
%F A130876 G.f.: (1 + 1727*x + x^2)/(1-x)^3.
%F A130876 E.g.f.: exp(x)*(1 + 1729*x*(2 + x)/2).
%F A130876 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2. (End)
%p A130876 a:= n-> 1+(1729/2)*n*(1+n):
%p A130876 seq(a(n), n=0..35); # _Alois P. Heinz_, Jul 16 2013
%t A130876 LinearRecurrence[{3,-3,1},{1,1730,5188},40] (* or *) Table[1+(1729/2)n(n+1), {n,0,40}] (* _Harvey P. Dale_, May 22 2017 *)
%o A130876 (PARI) a(n) = 1 + (1729/2)*n + (1729/2)*n^2 \\ _Michel Marcus_, Jul 16 2013
%Y A130876 Cf. A130859.
%K A130876 nonn,easy
%O A130876 0,2
%A A130876 _N. J. A. Sloane_, Oct 06 2007, based on a suggestion from Anton Mravcek in 2004