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 A256650 #36 Aug 04 2025 14:21:10
%S A256650 0,1,31,118,290,575,1001,1596,2388,3405,4675,6226,8086,10283,12845,
%T A256650 15800,19176,23001,27303,32110,37450,43351,49841,56948,64700,73125,
%U A256650 82251,92106,102718,114115,126325,139376,153296,168113,183855,200550,218226,236911,256633
%N A256650 30-gonal pyramidal numbers: a(n) = n*(n+1)*(28*n-25)/6.
%C A256650 See comments in A256645.
%C A256650 This sequence is related to A051868 by a(n) = n*A051868(n) - Sum_{i=0..n-1} A051868(i). [_Bruno Berselli_, Apr 09 2015]
%D A256650 E. Deza and M. M. Deza, Figurate numbers, World Scientific Publishing (2012), page 93 (28th row of the table).
%H A256650 Luciano Ancora, <a href="/A256650/b256650.txt">Table of n, a(n) for n = 0..1000</a>
%H A256650 Luciano Ancora, <a href="/A256645/a256645_1.pdf">Polygonal and Pyramidal numbers</a>, Section 3.
%H A256650 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A256650 G.f.: x*(1 + 27*x)/(1 - x)^4.
%F A256650 a(n) = A000292(n) + 27*A000292(n-1).
%F A256650 From _Elmo R. Oliveira_, Aug 04 2025: (Start)
%F A256650 E.g.f.: exp(x)*x*(6 + 87*x + 28*x^2)/6.
%F A256650 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
%t A256650 Table[n (n + 1) (28 n - 25)/6, {n, 0, 40}]
%t A256650 LinearRecurrence[{4, -6, 4, -1}, {0, 1, 31, 118}, 40] (* _Vincenzo Librandi_, Apr 08 2015 *)
%o A256650 (Magma) [n*(n+1)*(28*n-25)/6: n in [0..50]]; // _Vincenzo Librandi_, Apr 08 2015
%Y A256650 Partial sums of A254474.
%Y A256650 Cf. similar sequences listed in A237616.
%Y A256650 Cf. A000292, A051868, A256645.
%K A256650 nonn,easy
%O A256650 0,3
%A A256650 _Luciano Ancora_, Apr 07 2015