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.

A102321 Column 0 of triangular matrix A102320, which satisfies T(n,k) = [T^2](n-1,k) when n>k>=0, with T(n,n) = (2*n+1).

Original entry on oeis.org

1, 1, 4, 33, 436, 8122, 197920, 6007205, 219413116, 9402081718, 463548752912, 25893783163498, 1618536618626888, 112053082721454708, 8518619080226661504, 705977323976245345133, 63382036275445226941548
Offset: 0

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Author

Paul D. Hanna, Jan 05 2005

Keywords

Examples

			G.f.: 1 = (1-x) + 1*x*(1-x)(1-3x) + 4*x^2*(1-x)(1-3x)(1-5x) + ... + a(n)*x^n*(1-x)(1-3x)(1-5x)*..*(1-(2n+1)*x) + ...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=Mat(1),B); for(m=2,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=2*j-1,if(j==1,B[i,j]=(A^2)[i-1,1], B[i,j]=(A^2)[i-1,j]));));A=B);return(A[n+1,1])}
    
  • PARI
    {a(n)=if(n==0,1,polcoeff(1-sum(k=0,n-1,a(k)*x^k*prod(j=0,k,1-(2*j+1)*x+x*O(x^n))),n))}

Formula

G.f.: 1 = Sum_{n>=0} a(n)*x^n*prod_{k=0, n} (1-(2k+1)*x) for n>0 with a(0)=1.

A102322 Column 1 of triangular matrix A102320, which that satisfies: T(n,k) = [T^2](n-1,k) when n>k>=0, with T(n,n) = (2*n+1).

Original entry on oeis.org

0, 3, 9, 72, 945, 17568, 427770, 12979080, 473981445, 20308813128, 1001231706582, 55927084380552, 3495759750651978, 242012640619081152, 18398411206663695732, 1524754064472700613328, 136890662566189661556525
Offset: 0

Views

Author

Paul D. Hanna, Jan 05 2005

Keywords

Crossrefs

Programs

  • PARI
    {a(n)=local(A=Mat([1,0;1,1]),B); for(m=2,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=2*j-1,if(j==1,B[i,j]=(A^2)[i-1,1], B[i,j]=(A^2)[i-1,j]));));A=B);return(A[n+1,2])}

A102323 Triangle, read by rows, where T(n,k) = T(n,k-1) + (2*k+1)*T(n-1,k) for n>k>0, T(n,0)=1 and T(n,n) = T(n,n-1) for n>=0.

Original entry on oeis.org

1, 1, 1, 1, 4, 4, 1, 13, 33, 33, 1, 40, 205, 436, 436, 1, 121, 1146, 4198, 8122, 8122, 1, 364, 6094, 35480, 108578, 197920, 197920, 1, 1093, 31563, 279923, 1257125, 3434245, 6007205, 6007205, 1, 3280, 161095, 2120556, 13434681, 51211376
Offset: 0

Views

Author

Paul D. Hanna, Jan 05 2005

Keywords

Comments

Main diagonal is A102321, which is column 0 of triangle A102320.

Examples

			T(5,2) = 1146 = 1*1 + 3*40 + 5*205 = 1*T(4,0) + 3*T(4,1) + 5*T(4,2).
T(5,2) = 1146 = 121 + 5*205 = T(5,1) + (2*2+1)*T(4,2).
T(5,3) = 4198 = 1146 + 7*436 = T(5,2) + (2*3+1)*T(4,3).
Rows begin:
[1],
[1,1],
[1,4,4],
[1,13,33,33],
[1,40,205,436,436],
[1,121,1146,4198,8122,8122],
[1,364,6094,35480,108578,197920,197920],
[1,1093,31563,279923,1257125,3434245,6007205,6007205],...
		

Crossrefs

Programs

  • PARI
    T(n,k)=if(n
    				
Showing 1-3 of 3 results.