cp's OEIS Frontend

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.

A124540 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_k(y)^n ]^n for n>=0, with R_0(y) = 1.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 7, 5, 0, 1, 4, 15, 26, 16, 0, 1, 5, 26, 73, 107, 62, 0, 1, 6, 40, 156, 369, 486, 274, 0, 1, 7, 57, 285, 939, 1959, 2398, 1332, 0, 1, 8, 77, 470, 1995, 5764, 10912, 12668, 6978, 0, 1, 9, 100, 721, 3756, 13976, 36248, 63543, 70863, 38873, 0
Offset: 0

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Author

Paul D. Hanna, Nov 05 2006

Keywords

Comments

Antidiagonal sums equal row 1 (A124531).

Examples

			Row g.f.s R_n(y) simultaneously satisfy:
R_n(y) = [1 + y*R_1(y)^n + y^2*R_2(y)^n + y^3*R_3(y)^n +...]^n
more explicitly:
R_0 = [1 + y + y^2 + y^3 + y^4 + ...]^0 = 1;
R_1 = [1 + y*(R_1)^1 + y^2*(R_2)^1 + y^3*(R_3)^1 + y^4*(R_4)^1 +...]^1;
R_2 = [1 + y*(R_1)^2 + y^2*(R_2)^2 + y^3*(R_3)^2 + y^4*(R_4)^2 +...]^2;
R_3 = [1 + y*(R_1)^3 + y^2*(R_2)^3 + y^3*(R_3)^3 + y^4*(R_4)^3 +...]^3;
R_4 = [1 + y*(R_1)^4 + y^2*(R_2)^4 + y^3*(R_3)^4 + y^4*(R_4)^4 +...]^4;
etc., for all rows.
Table begins:
1,0,0,0,0,0,0,0,0,0,0,...
1,1,2,5,16,62,274,1332,6978,38873,228090,...
1,2,7,26,107,486,2398,12668,70863,416304,2552490,...
1,3,15,73,369,1959,10912,63543,385341,2424988,15788469,...
1,4,26,156,939,5764,36248,233900,1549193,10529052,73390856,...
1,5,40,285,1995,13976,98665,704810,5107950,37619020,281850156,...
1,6,57,470,3756,29658,233241,1836912,14543877,116087596,936035298,...
1,7,77,721,6482,57057,495922,4282895,36922550,318834341,2765000007,...
1,8,100,1048,10474,101800,970628,9140344,85445683,795971176,7410928800,...
1,9,126,1461,16074,171090,1777416,18151272,183201255,1834958107,...
1,10,155,1970,23665,273902,3081700,33954660,368443380,3954149640,...
1,11,187,2585,33671,421179,5104528,60398327,701775756,8042277034,...
1,12,222,3316,46557,626028,8133916,102916452,1275653922,15559229828,...
		

Crossrefs

Rows: A124531, A124542, A124543, A124544, A124545, A124546; diagonals: A124547, A124548, A124549; related tables: A124530, A124550, A124460.

Programs

  • PARI
    T(n,k)=local(m=max(n,k),R);R=vector(m+1,r,vector(m+1,c,if(r==1 || c<=2,1,r^(c-2)))); for(i=0,m, for(r=0,m, R[r+1]=Vec(sum(c=0,m, x^c*Ser(R[c+1])^(r*c)+O(x^(m+1)))))); Vec(Ser(R[n+1])^n+O(x^(k+1)))[k+1]

Formula

Let S_n(y) be the g.f. of row n in table A124530, then R_n(y) = S_n(y)^n and so S_n(y) = Sum_{k>=0} y^k * R_k(y)^n for n>=0, where R_n(y) is the g.f. of row n in this table.