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 A100188 #24 Sep 08 2022 08:45:15 %S A100188 1,6,27,84,205,426,791,1352,2169,3310,4851,6876,9477,12754,16815, %T A100188 21776,27761,34902,43339,53220,64701,77946,93127,110424,130025,152126, %U A100188 176931,204652,235509,269730,307551,349216 %N A100188 Polar structured meta-anti-diamond numbers, the n-th number from a polar structured n-gonal anti-diamond number sequence. %H A100188 Vincenzo Librandi, <a href="/A100188/b100188.txt">Table of n, a(n) for n = 1..10000</a> %H A100188 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5, -10, 10, -5, 1). %F A100188 a(n) = (1/6)*(2*n^4 - 2*n^2 + 6*n). %F A100188 G.f.: x*(1 + x + 7*x^2 - x^3)/(1-x)^5. - _Colin Barker_, Apr 16 2012 %F A100188 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5); a(1)=1, a(2)=6, a(3)=27, a(4)=84, a(5)=205. - _Harvey P. Dale_, May 11 2016 %F A100188 E.g.f.: (3*x + 6*x^2 + 6*x^3 + x^4)*exp(x)/3. - _G. C. Greubel_, Nov 08 2018 %e A100188 There are no 1- or 2-gonal anti-diamonds, so 1 and (2n+2) are the first and second terms since all the sequences begin as such. %t A100188 Table[(2n^4-2n^2+6n)/6,{n,40}] (* or *) LinearRecurrence[{5,-10,10,-5,1}, {1,6,27,84,205},40] (* _Harvey P. Dale_, May 11 2016 *) %o A100188 (Magma) [(1/6)*(2*n^4-2*n^2+6*n): n in [1..40]]; // _Vincenzo Librandi_, Aug 18 2011 %o A100188 (PARI) vector(40, n, (n^4 -n^2 +3*n)/3) \\ _G. C. Greubel_, Nov 08 2018 %Y A100188 Cf. A000578, A000447, A004466, A007588, A063521, A062523 - "polar" structured anti-diamonds; A100189 - "equatorial" structured meta-anti-diamond numbers; A006484 for other structured meta numbers; and A100145 for more on structured numbers. %K A100188 nonn,easy %O A100188 1,2 %A A100188 James A. Record (james.record(AT)gmail.com), Nov 07 2004