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 A264854 #20 Feb 16 2025 08:33:27
%S A264854 0,1,14,61,175,400,791,1414,2346,3675,5500,7931,11089,15106,20125,
%T A264854 26300,33796,42789,53466,66025,80675,97636,117139,139426,164750,
%U A264854 193375,225576,261639,301861,346550,396025,450616,510664,576521,648550,727125,812631,905464,1006031
%N A264854 a(n) = n*(n + 1)*(11*n^2 + 11*n - 10)/24.
%C A264854 Partial sums of centered 11-gonal (or hendecagonal) pyramidal numbers.
%H A264854 OEIS Wiki, <a href="https://oeis.org/wiki/Figurate_numbers">Figurate numbers</a>
%H A264854 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PyramidalNumber.html">Pyramidal Number</a>
%H A264854 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A264854 G.f.: x*(1 + 9*x + x^2)/(1 - x)^5.
%F A264854 a(n) = Sum_{k = 0..n} A004467(k).
%F A264854 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5). - _Vincenzo Librandi_, Nov 27 2015
%t A264854 Table[n (n + 1) (11 n^2 + 11 n - 10)/24, {n, 0, 50}]
%o A264854 (Magma) [n*(n+1)*(11*n^2+11*n-10)/24: n in [0..50]]; // _Vincenzo Librandi_, Nov 27 2015
%o A264854 (PARI) a(n)=n*(n+1)*(11*n^2+11*n-10)/24 \\ _Charles R Greathouse IV_, Jul 26 2016
%Y A264854 Cf. A004467.
%Y A264854 Cf. similar sequences provided by the partial sums of centered k-gonal pyramidal numbers: A006522 (k=1), A006007 (k=2), A002817 (k=3), A006325 (k=4), A006322 (k=5), A000537 (k=6), A006323 (k=7), A006324 (k=8), A236770 (k=9), A264853 (k=10), this sequence (k=11), A062392 (k=12), A264888 (k=13).
%K A264854 nonn,easy
%O A264854 0,3
%A A264854 _Ilya Gutkovskiy_, Nov 26 2015