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.

Showing 1-3 of 3 results.

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

Views

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.

A124548 Secondary diagonal of rectangular table A124540: a(n) = A124540(n+1,n).

Original entry on oeis.org

1, 2, 15, 156, 1995, 29658, 495922, 9140344, 183201255, 3954149640, 91212812647, 2235185965152, 57899260705117, 1578806923315370, 45158965541429475, 1350797823601721136, 42141425201135893387, 1367978583480857293770
Offset: 0

Views

Author

Paul D. Hanna, Nov 05 2006

Keywords

Comments

In table A124540, the g.f. of row n, R_n(y), simultaneously satisfies: R_n(y) = [ Sum_{k>=0} y^k*R_k(y)^n ]^n for n>=0.

Crossrefs

Programs

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

Formula

a(n) is divisible by (n+1): a(n)/(n+1) = A124549(n).

A124549 Derived from a diagonal of rectangular table A124540: a(n) = A124540(n+1,n)/(n+1).

Original entry on oeis.org

1, 1, 5, 39, 399, 4943, 70846, 1142543, 20355695, 395414964, 8292073877, 186265497096, 4453789285009, 112771923093955, 3010597702761965, 84424863975107571, 2478907364772699611, 75998810193380960765
Offset: 0

Views

Author

Paul D. Hanna, Nov 05 2006

Keywords

Comments

In table A124540, the g.f. of row n, R_n(y), simultaneously satisfies: R_n(y) = [ Sum_{k>=0} y^k*R_k(y)^n ]^n for n>=0.

Crossrefs

Programs

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

Formula

a(n) = A124548(n)/(n+1).
Showing 1-3 of 3 results.