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 A129839 #28 Dec 07 2019 12:18:25 %S A129839 0,0,0,1,36,625,8100,90601,933156,9150625,87048900,812307001, %T A129839 7486748676,68447640625,622473660900,5641104760201,51003678922596, %U A129839 460438253730625,4152386009780100,37422167780506201,337103845136750916,3035761307578140625,27332814735512302500 %N A129839 a(n) = Stirling_2(n,3)^2. %H A129839 H. S. Wilf, <a href="http://www.math.upenn.edu/~wilf/website/dek.pdf">A lot of toast, with a side order of roast</a>, manuscript, Jan 04 2002. %H A129839 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (25,-239,1115,-2664,3060,-1296). %F A129839 G.f.: x^3*(1+11*x-36*x^2-36*x^3)/((1-x)*(1-2*x)*(1-3*x)*(1-4*x)*(1-6*x)*(1-9*x)). %F A129839 a(n) = (3^n - 3*2^n + 3)^2/36 for n>0. - _Charles R Greathouse IV_, Jan 03 2013 %t A129839 StirlingS2[Range[0,30],3]^2 (* _Harvey P. Dale_, Jan 03 2013 *) %o A129839 (Sage)[stirling_number2(n,3)^2for n in range(0,23)] # _Zerinvary Lajos_, Mar 14 2009 %o A129839 (PARI) a(n)=(3^n-3<<n+3)^2/36 \\ _Charles R Greathouse IV_, Jan 03 2013 %Y A129839 Cf. A000392. %K A129839 nonn,easy %O A129839 0,5 %A A129839 _N. J. A. Sloane_, Feb 08 2008 %E A129839 Definition corrected (exponent changed from 3 to 2) by _Harvey P. Dale_, Jan 03 2013