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 A100155 #19 Aug 06 2025 08:40:48
%S A100155 1,24,103,272,565,1016,1659,2528,3657,5080,6831,8944,11453,14392,
%T A100155 17795,21696,26129,31128,36727,42960,49861,57464,65803,74912,84825,
%U A100155 95576,107199,119728,133197,147640,163091,179584,197153,215832,235655,256656,278869,302328
%N A100155 Structured truncated octahedral numbers.
%H A100155 Vincenzo Librandi, <a href="/A100155/b100155.txt">Table of n, a(n) for n = 1..5000</a>
%H A100155 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A100155 a(n) = (1/3)*n*(17*n^2 - 18*n + 4).
%F A100155 G.f.: x*(1 + 20*x + 13*x^2)/(1-x)^4. - _Colin Barker_, Feb 12 2012
%F A100155 From _Elmo R. Oliveira_, Aug 05 2025: (Start)
%F A100155 E.g.f.: exp(x)*x*(17*x^2 + 33*x + 3)/3.
%F A100155 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 4. (End)
%t A100155 LinearRecurrence[{4, -6, 4, -1}, {1, 24, 103, 272}, 50] (* _Paolo Xausa_, Aug 06 2025 *)
%o A100155 (Magma) [(1/6)*(34*n^3-36*n^2+8*n): n in [1..40]]; // _Vincenzo Librandi_, Jul 19 2011
%Y A100155 Cf. A100154, A100156 for adjacent structured Archimedean solids; A100145 for more on structured polyhedral numbers. Similar to truncated octahedral numbers A005910.
%K A100155 easy,nonn
%O A100155 1,2
%A A100155 James A. Record (james.record(AT)gmail.com), Nov 07 2004