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.

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A142707 Coefficients of derivatives of MacMahon polynomials (A060187): p(x,n)=2^n*(1 - x)^(1 + n)*LerchPhi[x, -n, 1/2]; p'(x,n)=(d/dx)p{x,n).

Original entry on oeis.org

1, 6, 2, 23, 46, 3, 76, 460, 228, 4, 237, 3364, 5046, 948, 5, 722, 21086, 70644, 42172, 3610, 6, 2179, 121314, 779169, 1038892, 303285, 13074, 7, 6552, 663224, 7455864, 18700056, 12426440, 1989672, 45864, 8, 19673, 3512680, 65123916, 277653176
Offset: 1

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Author

Roger L. Bagula and Gary W. Adamson, Sep 24 2008

Keywords

Comments

Row sums are:A014479
0, 1, 8, 72, 768, 9600, 138240, 2257920, 41287680, 836075520, 18579456000.

Examples

			{1},
{6, 2},
{23, 46, 3},
{76, 460, 228, 4},
{237, 3364, 5046, 948, 5},
{722, 21086, 70644, 42172, 3610, 6},
{2179, 121314, 779169, 1038892, 303285, 13074, 7},
{6552, 663224, 7455864, 18700056, 12426440, 1989672, 45864, 8},
{19673, 3512680, 65123916, 277653176, 347066470, 130247832, 12294380, 157384, 9},
{59038, 18232282, 534902712, 3627693128, 7635462340, 5441539692, 1248106328, 72929128, 531342, 10}
		

Crossrefs

Programs

  • Mathematica
    Clear[p, x, n, a]; p[x_, n_] = 2^n*(1 - x)^(1 + n)*LerchPhi[x, -n, 1/2]; Table[FullSimplify[Expand[D[p[x, n], x]]], {n, 0, 10}]; Table[CoefficientList[FullSimplify[Expand[D[p[x, n], x]]], x], {n, 0, 10}]; Flatten[%]

Formula

p(x,n)=2^n*(1 - x)^(1 + n)*LerchPhi[x, -n, 1/2]; p'(x,n)=(d/dx)p{x,n); t(n,m)=Coefficients(p'(x,n)).

A225474 Triangle read by rows, k!*2^k*s_2(n, k) where s_m(n, k) are the Stirling-Frobenius cycle numbers of order m; n >= 0, k >= 0.

Original entry on oeis.org

1, 1, 2, 3, 8, 8, 15, 46, 72, 48, 105, 352, 688, 768, 384, 945, 3378, 7600, 11040, 9600, 3840, 10395, 39048, 97112, 167040, 193920, 138240, 46080, 135135, 528414, 1418648, 2754192, 3857280, 3736320, 2257920, 645120, 2027025, 8196480, 23393376, 49824768, 79892736
Offset: 0

Views

Author

Peter Luschny, May 19 2013

Keywords

Comments

The Stirling-Frobenius cycle numbers are defined in A225470.

Examples

			[n\k][ 0,    1,    2,     3,    4,    5]
[0]    1,
[1]    1,    2,
[2]    3,    8,    8,
[3]   15,   46,   72,    48,
[4]  105,  352,  688,   768,  384,
[5]  945, 3378, 7600, 11040, 9600, 3840.
		

Crossrefs

Programs

  • Mathematica
    SFCSO[n_, k_, m_] := SFCSO[n, k, m] = If[k>n || k<0, 0, If[n == 0 && k == 0, 1, m*k*SFCSO[n-1, k-1, m] + (m*n-1)*SFCSO[n-1, k, m]]]; Table[SFCSO[n, k, 2], {n, 0, 8}, {k, 0, n}] // Flatten (* Jean-François Alcover, Feb 05 2014, translated from Sage *)
  • Sage
    @CachedFunction
    def SF_CSO(n, k, m):
        if k > n or k < 0 : return 0
        if n == 0 and k == 0: return 1
        return m*k*SF_CSO(n-1, k-1, m) + (m*n-1)*SF_CSO(n-1, k, m)
    for n in (0..8): [SF_CSO(n, k, 2) for k in (0..n)]

Formula

For a recurrence see the Sage program.
T(n, 0) ~ A001147; T(n, n) ~ A000165; T(n, n-1) ~ A014479.
T(n,k) = A028338(n,k) * A000165(k) = A225475(n,k) * A000079(k) = A161198(n,k) * A000142(k). - Philippe Deléham, Jun 25 2015

A255908 Triangle read by rows: T(n,L) = number of rho-labeled graphs with n edges whose labeling is bipartite with boundary value L.

Original entry on oeis.org

2, 4, 8, 8, 32, 48, 16, 128, 288, 384, 32, 512, 1728, 3072, 3840, 64, 2048, 10368, 24576, 38400, 46080, 128, 8192, 62208, 196608, 384000, 552960, 645120, 256, 32768, 373248, 1572864, 3840000, 6635520, 9031680, 10321920, 512, 131072, 2239488, 12582912, 38400000, 79626240, 126443520, 165150720, 185794560, 1024, 524288, 13436928, 100663296, 384000000, 955514880, 1770209280, 2642411520, 3344302080, 3715891200
Offset: 1

Views

Author

Keywords

Comments

A graph with n edges is rho-labeled if there exists a one-to-one mapping from its vertex set to {0,1,...,2n} such that every edge receives as label the absolute difference of its end-vertices and the edge labels are x_1, x_2, ..., x_n where x_i = i or x_i = 2n + 1 - i. A rho-labeling of a bipartite graph is said to be bipartite when the labels of one stable set are smaller than the labels on the other stable set. The largest of the smaller vertex labels is its boundary value.
From Robert G. Wilson v, Jul 05 2015: (Start)
The columns:
T(n, 0) = 2^n,
T(n, 1) = 2^(2n-1),
T(n, 2) = 2^(n+1)*3^(n-2),
T(n, 3) = 3*2^(3n-5),
T(n, 4) = 3*2^(n+3)*5^(n-4),
T(n, 5) = 5*2^(2n-2)*3^(n-4), etc.
The diagonals:
the main, T(n, n-1) = 2^n*n*(n-1!) = 2*A002866,
the second diagonal, T(n, n-2) = 2^n*(n-1)^2*(n-2)! = 4*A014479,
the third diagonal, T(n, n-3) = 2^n*(n-2)^3*(n-3)!,
the k_th diagonal, T(n, n-k) = 2^n*(n-k)^k*(n-k)!, etc.
... (End)

Examples

			For n=5 and L=1, T(5,1)=(2^5)*(1!)*(1+1)^(5-1)=512.
For n=9 and L=3, T(9,3)=12582912.
Triangle, T, begins:
-----------------------------------------------------------------------------
n\L |   0       1         2          3          4          5           6
----|------------------------------------------------------------------------
1   |   2;
2   |   4,      8;
3   |   8,     32,       48;
4   |  16,    128,      288,       384;
5   |  32,    512,     1728,      3072,      3840;
6   |  64,   2048,    10368,     24576,     38400,     46080;
7   | 128,   8192,    62208,    196608,    384000,    552960,     645120;
8   | 256,  32768,   373248,   1572864,   3840000,   6635520,    9031680, ...
...
For n=2 and L=1, T(2,1)=8, because: the bipartite graph <{v1,v2,v3},{x1=v1v2,x2=v1v3}> has rho-labelings (2,1,3),(2,1,4) with L=1 on the stable set {x2} and rho-labelings (1,2,0),(0,4,1) with L=1 on the stable set {x1,x3}; the bipartite graph <{v1,v2,v3,v4},{x1=v1v2,x2=v3v4}> has rho-labeling (0,4,1,3),(1,2,0,3) with L=1 on the stable set {v1,v3} and rho-labeling (4,0,3,1),(2,1,3,0) with L=1 on the stable set {v2,v4}. - _Danny Rorabaugh_, Apr 03 2015
		

Programs

  • Magma
    [2^n*Factorial(l)*(l+1)^(n-l): l in [0..n-1], n in [1..10]]; // Bruno Berselli, Aug 05 2015
  • Mathematica
    t[n_, l_] := 2^n*l!(l+1)^(n-l); Table[ t[n, l], {n, 8}, {l, 0, n-1}] // Flatten (* Robert G. Wilson v, Jul 05 2015 *)

Formula

For n>=1, 0<=L<=n-1, T(n,L)=(2^n)*(L!)*(L+1)^(n-L).
Previous Showing 11-13 of 13 results.