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.

A059594 Convolution triangle based on A008619 (positive integers repeated).

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 2, 5, 3, 1, 3, 8, 9, 4, 1, 3, 14, 19, 14, 5, 1, 4, 20, 39, 36, 20, 6, 1, 4, 30, 69, 85, 60, 27, 7, 1, 5, 40, 119, 176, 160, 92, 35, 8, 1, 5, 55, 189, 344, 376, 273, 133, 44, 9, 1, 6, 70, 294, 624, 820, 714, 434
Offset: 0

Views

Author

Wolfdieter Lang, Feb 02 2001

Keywords

Comments

In the language of the Shapiro et al. reference (given in A053121) such a lower triangular (ordinary) convolution array, considered as a matrix, belongs to the Bell-subgroup of the Riordan-group.
The G.f. for the row polynomials p(n,x) = Sum_{m=0..n} a(n,m)*x^m is 1/((1-z^2)*(1-z)-x*z).
The column sequences are A008619(n); A006918(n); A038163(n-2), n >= 2; A038164(n-3), n >= 3; A038165(n-4), n >= 4; A038166(n-5), n >= 5; A059595(n-6), n >= 6; A059596(n-7), n >= 7; A059597(n-8), n >= 8; A059598(n-9), n >= 9; A059625(n-10), n >= 10 for m=0..10.
The sequence of row sums is A006054(n+2).
From Gary W. Adamson, Aug 14 2016: (Start)
The sequence can be generated by extracting the descending antidiagonals of an array formed by taking powers of the natural integers with repeats, (1, 1, 2, 2, 3, 3, ...), as follows:
1, 1, 2, 2, 3, 3, ...
1, 2, 5, 8, 14, 20, ...
1, 3, 9, 19, 39, 69, ...
1, 4, 14, 36, 85, 176, ...
...
Row sums of the triangle = (1, 2, 5, 11, 25, 56, ...), the INVERT transform of (1, 1, 2, 2, 3, 3, ...). (End)

Examples

			{1}; {1,1}; {2,2,1}; {2,5,3,1}; ...
Fourth row polynomial (n=3): p(3,x)= 2 + 5*x + 3*x^2 + x^3.
		

Programs

  • Mathematica
    t[n_, m_] := Sum[Sum[Binomial[j, n-m-3*k+2*j]*(-1)^(j-k)*Binomial[k, j], {j, 0, k}]*Binomial[m+k, m], {k, 0, n-m}]; Table[t[n, m], {n, 0, 10}, {m, 0, n}] // Flatten (* Jean-François Alcover, May 27 2013, after Vladimir Kruchinin *)
  • Maxima
    T(n,m):=sum((sum(binomial(j,n-m-3*k+2*j)*(-1)^(j-k)*binomial(k,j),j,0,k)) *binomial(m+k,m),k,0,n-m); /* Vladimir Kruchinin, Dec 14 2011 */

Formula

a(n, m) := a(n-1, m) + (-(n-m+1)*a(n, m-1) + 3*(n+2*m)*a(n-1, m-1))/(8*m), n >= m >= 1; a(n, 0) := floor((n+2)/2) = A008619(n), n >= 0; a(n, m) := 0 if n < m.
G.f.for column m >= 0: ((x/((1-x^2)*(1-x)))^m)/((1-x^2)*(1-x)).
T(n,m) = Sum_{k=0..n-m} (Sum_{j=0..k} binomial(j, n-m-3*k+2*j)*(-1)^(j-k)*binomial(k,j))*binomial(m+k,m). - Vladimir Kruchinin, Dec 14 2011
Recurrence: T(n,k) = T(n-1,k) + T(n-1,k-1) + T(n-2,k) - T(n-3,k) with T(0,0) = 1. - Philippe Deléham, Feb 23 2012

A060100 Fifth column (m=4) of triangle A060098.

Original entry on oeis.org

1, 5, 19, 55, 140, 316, 660, 1284, 2370, 4170, 7062, 11550, 18348, 28380, 42900, 63492, 92235, 131703, 185185, 256685, 351208, 474760, 634712, 839800, 1100580, 1429428, 1841100, 2352732, 2984520, 3759720, 4705464, 5852760, 7237461, 8900265, 10887855
Offset: 0

Views

Author

Wolfdieter Lang, Apr 06 2001

Keywords

Comments

Partial sums of A038164.

Programs

  • PARI
    Vec(1 / ((1-x)^9*(1+x)^4) + O(x^40)) \\ Colin Barker, Jan 17 2017

Formula

a(n)= sum(A060098(n+4, 4)).
G.f.: 1/((1-x^2)^4*(1-x)^5) = 1/((1-x)^9*(1+x)^4).
a(n) = (315*(3797+299*(-1)^n) + 12*(204347+4165*(-1)^n)*n + 2*(970241+4095*(-1)^n)*n^2 + 28*(28457+15*(-1)^n)*n^3 + 189168*n^4 + 26936*n^5 + 2268*n^6 + 104*n^7 + 2*n^8) / 1290240. - Colin Barker, Jan 17 2017

A059600 Expansion of (1+6*x+x^2)/(1-x)^8.

Original entry on oeis.org

1, 14, 85, 344, 1086, 2892, 6798, 14520, 28743, 53482, 94523, 159952, 260780, 411672, 631788, 945744, 1384701, 1987590, 2802481, 3888104, 5315530, 7170020, 9553050, 12584520, 16405155, 21179106, 27096759
Offset: 0

Views

Author

Wolfdieter Lang, Feb 02 2001

Keywords

Comments

a(n)= A038164(2*n).

Programs

  • Mathematica
    CoefficientList[Series[(1+6x+x^2)/(1-x)^8,{x,0,30}],x] (* or *) LinearRecurrence[ {8,-28,56,-70,56,-28,8,-1},{1,14,85,344,1086,2892,6798,14520},30] (* Harvey P. Dale, Aug 18 2024 *)

Formula

a(n)= binomial(n+5, 5)*(4*n^2+24*n+21)/21.
G.f.: (1+6*x+x^2)/(1-x)^8.
Showing 1-3 of 3 results.