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 A347319 #16 Dec 24 2024 02:15:42 %S A347319 1,3,15,91,333,891,1963,3795,6681,10963,17031,25323,36325,50571,68643, %T A347319 91171,118833,152355,192511,240123,296061,361243,436635,523251,622153, %U A347319 734451,861303,1003915,1163541,1341483,1539091,1757763,1998945,2264131,2554863,2872731,3219373,3596475,4005771 %N A347319 a(n) = (2*n+1)*(n^3-2*n^2+n+1). %H A347319 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1). %F A347319 From _Chai Wah Wu_, Sep 12 2021: (Start) %F A347319 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 4. %F A347319 G.f.: (-3*x^4 - 36*x^3 - 10*x^2 + 2*x - 1)/(x - 1)^5. (End) %o A347319 (Python) %o A347319 def A347319(n): return n*(n**2*(2*n - 3) + 3) + 1 # _Chai Wah Wu_, Sep 12 2021 %o A347319 (PARI) a(n)=(2*n+1)*(n^3-2*n^2+n+1) \\ _Charles R Greathouse IV_, Oct 21 2022 %Y A347319 A bisection of A146212, analogous to A344866 and A344907. %K A347319 nonn,easy %O A347319 0,2 %A A347319 _N. J. A. Sloane_, Sep 12 2021