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 A124550 #4 Mar 30 2012 18:37:01 %S A124550 1,1,0,1,1,0,1,2,2,0,1,3,7,5,0,1,4,15,30,16,0,1,5,26,91,159,66,0,1,6, %T A124550 40,204,666,1056,348,0,1,7,57,385,1899,5955,8812,2321,0,1,8,77,650, %U A124550 4345,21180,65794,92062,19437,0,1,9,100,1015,8616,57876,287568,901881 %N A124550 Rectangular table, read by antidiagonals, such that the g.f. of row n, R_n(y), satisfies: R_n(y) = [ Sum_{k>=0} y^k * R_{n*k}(y) ]^n for n>=0, with R_0(y)=1. %C A124550 Antidiagonal sums equal row 1 (A124551). %F A124550 Let G_n(y) be the g.f. of row n in table A124560, then R_n(y) = G_n(y)^n and thus G_n(y) = Sum_{k>=0} y^k * R_{n*k}(y) for n>=0, where R_n(y) is the g.f. of row n in this table. %e A124550 The g.f. of row n, R_n(y), simultaneously satisfies: %e A124550 R_n(y) = [1 + y*R_{n}(y) + y^2*R_{2n}(y) + y^3*R_{3n}(y) +...]^n %e A124550 more explicitly, %e A124550 R_0 = [1 + y + y^2 + y^3 +... ]^0 = 1, %e A124550 R_1 = [1 + y*R_1 + y^2*R_2 + y^3*R_3 + y^4*R_4 +...]^1, %e A124550 R_2 = [1 + y*R_2 + y^2*R_4 + y^3*R_6 + y^4*R_8 +...]^2, %e A124550 R_3 = [1 + y*R_3 + y^2*R_6 + y^3*R_9 + y^4*R_12 +...]^3, %e A124550 R_4 = [1 + y*R_4 + y^2*R_8 + y^3*R_12 + y^4*R_16 +...]^4, %e A124550 etc., for all rows. %e A124550 Table begins: %e A124550 1,0,0,0,0,0,0,0,0,0,... %e A124550 1,1,2,5,16,66,348,2321,19437,203554,2661035,43399794,883165898,... %e A124550 1,2,7,30,159,1056,8812,92062,1200415,19512990,395379699,9991017068,... %e A124550 1,3,15,91,666,5955,65794,901881,15346419,324465907,8535776700,... %e A124550 1,4,26,204,1899,21180,287568,4802716,99084889,2531896840,... %e A124550 1,5,40,385,4345,57876,926340,18088835,434349525,12879458545,... %e A124550 1,6,57,650,8616,133212,2447115,54419202,1481595429,49675372516,... %e A124550 1,7,77,1015,15449,271677,5621371,139777303,4236941723,157754261392,... %e A124550 1,8,100,1496,25706,506376,11637540,319211576,10629219251,... %e A124550 1,9,126,2109,40374,880326,22228296,665618589,24097683942,... %e A124550 1,10,155,2870,60565,1447752,39814650,1290831110,50395939380,... %e A124550 1,11,187,3795,87516,2275383,67666852,2359273213,98672395096,... %e A124550 1,12,222,4900,122589,3443748,110082100,4104444564,182882370066,... %e A124550 1,13,260,6201,167271,5048472,172579056,6848496031,323591733868,... %e A124550 1,14,301,7714,223174,7201572,262109169,11025158762,550236760920,... %e A124550 1,15,345,9455,292035,10032753,387284805,17206288875,903909656190,... %e A124550 1,16,392,11440,375716,13690704,558624184,26132289904,1440743993738,... %e A124550 1,17,442,13685,476204,18344394,788813124,38746675145,2235979092419,... %e A124550 1,18,495,16206,595611,24184368,1092983592,56235032046,3388787136045,... %e A124550 1,19,551,19019,736174,31424043,1489009062,80068650785,5027951628273,... %e A124550 1,20,610,22140,900255,40301004,1997816680,112053079180,7318490555455,... %e A124550 1,21,672,25585,1090341,51078300,2643716236,154381866075,10469322413655,.. %e A124550 1,22,737,29370,1309044,64045740,3454745943,209695755346,14742078039007,.. %e A124550 1,23,805,33511,1559101,79521189,4463035023,281147592671,20461165963557,.. %e A124550 1,24,876,38024,1843374,97851864,5705183100,372473207208,28025203801701,.. %o A124550 (PARI) {T(n,k)=if(k==0,1,if(n==0,0,if(k==1,n,if(n<=k, Vec(( 1+x*Ser( vector(k,j,sum(i=0,j-1,T(n+i*n,j-1-i)) ) ))^n)[k+1], Vec(subst(Ser(concat(concat(0, Vec(subst(Ser(vector(k+1,j,T(j-1,k))),x,x/(1+x))/(1+x))),vector(n-k+1)) ),x,x/(1-x))/(1-x +x*O(x^(n))))[n]))))} %Y A124550 Rows: A124551, A124552, A124553, A124554, A124555, A124556; diagonals: A124557, A124558, A124559; variants: A124560, A124460, A124530, A124540. %K A124550 nonn,tabl %O A124550 0,8 %A A124550 _Paul D. Hanna_, Nov 07 2006