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.

A124727 Triangle read by rows: T(n,k)=k*binomial(n-1,k-1)+binomial(n-1,k) (1<=k<=n).

Original entry on oeis.org

1, 2, 2, 3, 5, 3, 4, 9, 10, 4, 5, 14, 22, 17, 5, 6, 20, 40, 45, 26, 6, 7, 27, 65, 95, 81, 37, 7, 8, 35, 98, 175, 196, 133, 50, 8, 9, 44, 140, 294, 406, 364, 204, 65, 9, 10, 54, 192, 462, 756, 840, 624, 297, 82, 10, 11, 65, 255, 690, 1302, 1722, 1590, 1005, 415, 101, 11, 12, 77
Offset: 1

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Author

Keywords

Comments

Triangle is P*M, where P is Pascal's triangle as an infinite lower triangular matrix and M is the infinite bidiagonal matrix with (1,2,3...) in the main diagonal and (1,1,1...) in the subdiagonal.

Examples

			First few rows of the triangle are:
1;
2, 2;
3, 5, 3;
4, 9, 10, 4;
5, 14, 22, 17, 5;
6, 20, 40, 45, 26, 6
...
		

Crossrefs

Row sums = A047859: (1, 4, 11, 27, 143, 319...) A124726 is generated in an analogous manner by taking M*P instead of P*M.

Programs

  • Maple
    T:=(n,k)->k*binomial(n-1,k-1)+binomial(n-1,k): for n from 1 to 12 do seq(T(n,k),k=1..n) od; # yields sequence in triangular form
  • Mathematica
    Flatten[Table[k Binomial[n-1,k-1]+Binomial[n-1,k],{n,20},{k,n}]] (* Harvey P. Dale, Jan 28 2012 *)

Extensions

Edited by N. J. A. Sloane, Nov 24 2006

A210381 Triangle by rows, derived from the beheaded Pascal's triangle, A074909.

Original entry on oeis.org

1, 0, 2, 0, 1, 3, 0, 1, 3, 4, 0, 1, 4, 6, 5, 0, 1, 5, 10, 10, 6, 0, 1, 6, 15, 20, 15, 7, 0, 1, 7, 21, 35, 35, 21, 8, 0, 1, 8, 28, 56, 70, 56, 28, 9, 0, 1, 9, 36, 84, 126, 126, 84, 36, 10, 0, 1, 10, 45, 120, 210, 252, 210, 120, 45, 11
Offset: 0

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Author

Roger L. Bagula and Gary W. Adamson, Mar 20 2012

Keywords

Comments

Row sums of the triangle = 2^n.
Let the triangle = an infinite lower triangular matrix, M. Then M * The Bernoulli numbers, A027641/A027642 as a vector V = [1, -1, 0, 0, 0,...]. M * the Bernoulli sequence variant starting [1, 1/2, 1/6,...] = [1, 1, 1,...]. M * 2^n: [1, 2, 4, 8,...] = A027649. M * 3^n = A255463; while M * [1, 2, 3,...] = A047859, and M * A027649 = A027650.
Row sums of powers of the triangle generate the Poly-Bernoulli number sequences shown in the array of A099594. - Gary W. Adamson, Mar 21 2012
Triangle T(n,k) given by (0, 1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (2, -1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 25 2012

Examples

			{1},
{0, 2},
{0, 1, 3},
{0, 1, 3, 4},
{0, 1, 4, 6, 5},
{0, 1, 5, 10, 10, 6},
{0, 1, 6, 15, 20, 15, 7},
{0, 1, 7, 21, 35, 35, 21, 8},
{0, 1, 8, 28, 56, 70, 56, 28, 9},
{0, 1, 9, 36, 84, 126, 126, 84, 36, 10},
{0, 1, 10, 45, 120, 210, 252, 210, 120, 45, 11}
...
		

References

  • Konrad Knopp, Elements of the Theory of Functions, Dover, 1952,pp 117-118.

Crossrefs

Programs

  • Mathematica
    t2[n_, m_] = If[m - 1 <= n, Binomial[n, m - 1], 0];
    O2 = Table[Table[If[n == m, t2[n, m] + 1, t2[n, m]], {m, 0, n}], {n, 0, 10}];
    Flatten[O2]

Formula

Partial differences of the beheaded Pascal's triangle A074909 starting from the top, by columns.
G.f.: (1-x)/(1-x-2*y*x+y*x^2+y^2*x^2). - Philippe Deléham, Mar 25 2012
T(n,k) = T(n-1,k) + 2*T(n-1,k-1) - T(n-2,k-1) - T(n-2,k-2), T(0,0) = T(2,1) = 1, T(1,0) = T(2,0) = 0, T(1,1) = 2, T(2,2) = 3 and T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Mar 25 2012

A131415 (A007318 * A000012) + (A000012 * A007318) - A007318.

Original entry on oeis.org

1, 3, 1, 6, 4, 1, 11, 10, 5, 1, 20, 21, 15, 6, 1, 37, 41, 36, 21, 7, 1, 70, 78, 77, 57, 28, 8, 1, 135, 148, 155, 134, 85, 36, 9, 1, 264, 283, 303, 289, 219, 121, 45, 10, 1, 521, 547, 586, 592, 508, 340, 166, 55, 11, 1
Offset: 0

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Author

Gary W. Adamson, Jul 08 2007

Keywords

Comments

Left column = A006127: (1, 3, 6, 11, 20, 37,...). Row sums = A047859: (1, 4, 11, 27, 63,...).

Examples

			First few rows of the triangle are:
1;
3, 1;
6, 4, 1;
11, 10, 5, 1;
20, 21, 15, 6, 1;
37, 41, 36, 21, 7, 1;
...
		

Crossrefs

Formula

(A007318 * A000012) + (A000012 * A007318) - A007318 as infinite lower triangular matrices.
Showing 1-3 of 3 results.