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.

A147294 Eigentriangle, row sums = A125275.

Original entry on oeis.org

1, 1, 1, 2, 3, 2, 5, 9, 10, 7, 14, 28, 40, 49, 31, 42, 90, 150, 245, 279, 162, 132, 297, 550, 1078, 1674, 1782, 968, 429, 1001, 2002, 4459, 8463, 12474, 12584, 6481, 1430, 3432, 7280, 17836, 39060, 71280, 100672, 97215, 47893
Offset: 1

Views

Author

Gary W. Adamson, Nov 05 2008

Keywords

Comments

Row sums = A125275 starting with offset 1: (1, 2, 7, 31, 162, 968,...).
Left border = A000108, right border = A125275.
Sum of n-th row terms = rightmost term of next row.

Examples

			First few rows of the triangle =
1;
1, 1;
2, 3, 2;
5, 9, 10, 7;
14, 28, 40, 49, 31;
42, 90, 150, 245, 279, 162;
132, 297, 550, 1078, 1674, 1782, 968;
429, 1001, 2002, 4459, 8463, 12474, 12584, 6481;
1430, 3432, 7280, 17836, 39060, 71280, 100672, 97215, 47893;
...
Row 4 = (5, 9, 10, 7) = termwise products of (5, 9, 5, 1) and (1, 1, 2, 7)
		

Crossrefs

Formula

A147294 = Triangle A039599 * (A125275 * 0^(n-k)); where (A125275 * 0^(n-k)) = an infinite lower triangular matrix with A125275: (1, 1, 2, 7, 31, 162,...) as the main diagonal and the rest zeros.

A144250 Eigentriangle, row sums = A125275, shifted.

Original entry on oeis.org

1, 1, 1, 1, 3, 2, 1, 6, 10, 6, 1, 10, 30, 42, 23, 1, 15, 70, 168, 207, 106, 1, 21, 140, 504, 1035, 1166, 567, 1, 28, 252, 1260, 3795, 6996, 7371, 3434
Offset: 0

Views

Author

Gary W. Adamson, Sep 16 2008

Keywords

Comments

Row sums = A125273 shifted. A125273 = the eigensequence of triangle A085478.
Right border = A125273: (1, 1, 2, 6, 23, 106, 567, 3434,...). Sum of n-th row terms = rightmost term in next row.

Examples

			First few rows of the triangle =
1;
1, 1;
1, 3, 2;
1, 6, 10, 6;
1, 10, 30, 42, 23;
1, 15, 70, 168, 207, 106;
1, 21, 140, 504, 1035, 1166, 567;
...
Row 4 = (1, 10, 30, 42, 23) = termwise products of (1, 10, 15, 7, 1) and (1, 1, 2, 6, 23) = (1*1, 10*1, 15*2, 7*6, 1*23); where (1, 10, 15, 7, 1) = row 4 of triangle A085478. Q
		

Crossrefs

Formula

Triangle read by rows, T(n,k) = A085478(n,k) * A125273(k).
As infinite lower triangular matrices, A144250 = A085478 * (A125275 * 0^(n-k); where (A125275 * 0^(n-k)) = an infinite lower triangular matrix with A125275: (1, 1, 2, 6, 23, 106, 567, 3434,...) as the main diagonal and the rest zeros.

Extensions

Corrected definition: Eigentriangle, row sums = A125273, shifted. - Gary W. Adamson, Nov 05 2008

A125276 Eigensequence of triangle A039598: a(n) = Sum_{k=0..n-1} A039598(n-1,k)*a(k) for n>0 with a(0)=1.

Original entry on oeis.org

1, 1, 3, 12, 58, 325, 2060, 14514, 112170, 941128, 8502393, 82160481, 844532873, 9191329357, 105491177081, 1272418794619, 16080824798705, 212370154398094, 2923859710010527, 41877072960374478, 622763691600244335
Offset: 0

Views

Author

Paul D. Hanna, Nov 26 2006

Keywords

Examples

			a(3) = 5*(1) + 4*(1) + 1*(3) = 12;
a(4) = 14*(1) + 14*(1) + 6*(3) + 1*(12) = 58;
a(5) = 42*(1) + 48*(1) + 27*(3) + 8*(12) + 1*(58) = 325.
Triangle A039598(n,k) = C(2*n+2,n-k)*(k+1)/(n+1) begins:
1;
2, 1;
5, 4, 1;
14, 14, 6, 1;
42, 48, 27, 8, 1;
132, 165, 110, 44, 10, 1; ...
where g.f. of column k = G000108(x)^(2*k+2)
and G000108(x) = (1 - sqrt(1-4*x))/(2x) is the Catalan function.
		

Crossrefs

Cf. A039598, A000108; A125275 (variant).

Programs

  • Mathematica
    A125276=ConstantArray[0,20]; A125276[[1]]=1; Do[A125276[[n]]=Binomial[2*n,n-1]/n+Sum[A125276[[k]]*Binomial[2*n,n-k-1]*(k+1)/n,{k,1,n-1}];,{n,2,20}]; Flatten[{1,A125276}] (* Vaclav Kotesovec, Dec 09 2013 *)
  • PARI
    a(n)=if(n==0,1,sum(k=0,n-1, a(k)*binomial(2*n, n-k-1)*(k+1)/n))

Formula

a(n) = Sum_{k=0..n-1} a(k) * C(2*n,n-k-1)*(k+1)/n for n>0 with a(0)=1.
G.f. A(x) satisfies: A(x/(1+x)^2) = 1 + x*A(x); also, A(x*(1-x)) = 1 + [x/(1-x)]*A(x/(1-x)); also, A(x) = 1 + x*C(x)^2*A(x*C(x)^2) where C(x) = (1 - sqrt(1-4x))/(2x) is the Catalan function (A000108). - Paul D. Hanna, Aug 15 2007
Showing 1-3 of 3 results.