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 1-5 of 5 results.

A000307 Number of 4-level labeled rooted trees with n leaves.

Original entry on oeis.org

1, 1, 4, 22, 154, 1304, 12915, 146115, 1855570, 26097835, 402215465, 6734414075, 121629173423, 2355470737637, 48664218965021, 1067895971109199, 24795678053493443, 607144847919796830, 15630954703539323090, 421990078975569031642, 11918095123121138408128
Offset: 0

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Author

Keywords

References

  • J. de la Cal, J. Carcamo, Set partitions and moments of random variables, J. Math. Anal. Applic. 378 (2011) 16 doi:10.1016/j.jmaa.2011.01.002 Remark 5
  • J. Ginsburg, Iterated exponentials, Scripta Math., 11 (1945), 340-353.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Example 5.2.4.

Crossrefs

a(n)=|A039812(n,1)| (first column of triangle).
Column k=3 of A144150.

Programs

  • Maple
    g:= proc(p) local b; b:= proc(n) option remember; `if`(n=0, 1, (n-1)! *add(p(k)*b(n-k)/ (k-1)!/ (n-k)!, k=1..n)) end end: a:= g(g(g(1))): seq(a(n), n=0..30);  # Alois P. Heinz, Sep 11 2008
  • Mathematica
    nn = 18; a = Exp[Exp[x] - 1]; b = Exp[a - 1];
    Range[0, nn]! CoefficientList[Series[Exp[b - 1], {x, 0, nn}], x]  (*Geoffrey Critzer, Dec 28 2011*)

Formula

E.g.f.: exp(exp(exp(exp(x)-1)-1)-1).
a(n) = sum(sum(sum(stirling2(n,k) *stirling2(k,m) *stirling2(m,r), k=m..n), m=r..n), r=1..n), n>0. - Vladimir Kruchinin, Sep 08 2010

Extensions

Extended with new definition by Christian G. Bower, Aug 15 1998

A039813 Matrix 5th power of Stirling2 triangle A008277.

Original entry on oeis.org

1, 5, 1, 35, 15, 1, 315, 215, 30, 1, 3455, 3325, 725, 50, 1, 44590, 56605, 17100, 1825, 75, 1, 660665, 1060780, 415555, 60900, 3850, 105, 1, 11035095, 21772595, 10606470, 1998605, 172550, 7210, 140, 1, 204904830, 486459105, 286281665, 66528210, 7346955, 417690, 12390, 180, 1
Offset: 1

Views

Author

Christian G. Bower, Feb 15 1999

Keywords

Examples

			Triangle begins:
      1;
      5,     1;
     35,    15,     1;
    315,   215,    30,    1;
   3455,  3325,   725,   50,  1;
  44590, 56605, 17100, 1825, 75, 1;
  ...
		

Crossrefs

Cf. A008277, A000357 (first column).

Programs

  • Mathematica
    max = 9; m = MatrixPower[Array[StirlingS2, {max, max}], 5]; Table[Take[m[[n]], n], {n, 1, max}] // Flatten (* Jean-François Alcover, Mar 03 2014 *)

Formula

E.g.f. k-th column: (( exp(exp(exp(exp(exp(x)-1)-1)-1)-1)-1 )^k)/k!. [corrected by Seiichi Manyama, Feb 12 2022]

A039811 Triangle read by rows: matrix cube of the Stirling2 triangle A008277.

Original entry on oeis.org

1, 3, 1, 12, 9, 1, 60, 75, 18, 1, 358, 660, 255, 30, 1, 2471, 6288, 3465, 645, 45, 1, 19302, 65051, 47838, 12495, 1365, 63, 1, 167894, 728556, 685580, 235193, 35700, 2562, 84, 1, 1606137, 8792910, 10285488, 4444188, 877653, 86940, 4410, 108, 1
Offset: 1

Views

Author

Christian G. Bower, Feb 15 1999

Keywords

Examples

			Triangle begins
     1;
     3,    1;
    12,    9,    1;
    60,   75,   18,   1;
   358,  660,  255,  30,  1;
  2471, 6288, 3465, 645, 45, 1;
  ...
		

Crossrefs

Cf. A008277, A000258 (first column).
Cf. also A039810, A039812, A039813.

Programs

  • Mathematica
    Flatten[Table[SeriesCoefficient[(Exp[Exp[Exp[x]-1]-1]-1)^k, {x,0,n}] n!/k!,{n,9}, {k,n}]] (* Stefano Spezia, Sep 12 2022 *)

Formula

E.g.f. k-th column: (( exp(exp(exp(x)-1)-1)-1 )^k)/k!. [corrected by Seiichi Manyama, Feb 12 2022]

A039816 Triangle read by rows: matrix 4th power of the Stirling-1 triangle A008275.

Original entry on oeis.org

1, -4, 1, 26, -12, 1, -234, 152, -24, 1, 2696, -2210, 500, -40, 1, -37919, 36976, -10710, 1240, -60, 1, 630521, -704837, 245896, -36750, 2590, -84, 1, -12111114, 15132932, -6120324, 1109696, -101500, 4816, -112, 1, 264051201, -362099010, 165387680, -34990620, 3901296, -241164, 8232, -144, 1
Offset: 1

Views

Author

Christian G. Bower, Feb 15 1999

Keywords

Examples

			Triangle begins:
       1;
      -4,     1;
      26,   -12,      1;
    -234,   152,    -24,    1;
    2696, -2210,    500,  -40,   1;
  -37919, 36976, -10710, 1240, -60, 1;
  ...
		

Crossrefs

Cf. A000310 (first column), A008275.

Programs

  • Maple
    T:= Matrix(10,10,(i,j) -> `if`(i>= j, combinat:-stirling1(i,j),0)):
    M:= T^4:
    seq(seq(M[i,j],j=1..i),i=1..10); # Robert Israel, Sep 12 2022
  • Mathematica
    Flatten[Table[SeriesCoefficient[(Log[1+Log[1+Log[1+Log[1+x]]]])^k,{x,0,n}] n!/k!, {n,9}, {k,n}]] (* Stefano Spezia, Sep 12 2022 *)

Formula

E.g.f. of k-th column: ((log(1+log(1+log(1+log(1+x)))))^k)/k!.

A351514 Expansion of e.g.f. (exp(exp(exp(exp(x)-1)-1)-1)-1)^2 / 2.

Original entry on oeis.org

1, 12, 136, 1650, 21904, 318521, 5051988, 86910426, 1612648066, 32107793135, 682724688430, 15439016490989, 369914992674530, 9359103270641290, 249292192469843244, 6971850327184526783, 204215496402215939638, 6251233458455082035922
Offset: 2

Views

Author

Seiichi Manyama, Feb 12 2022

Keywords

Crossrefs

Column 2 of A039812.

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace((exp(exp(exp(exp(x)-1)-1)-1)-1)^2/2))
    
  • PARI
    T(n, k) = if(k==0, n<=1, sum(j=0, n, stirling(n, j, 2)*T(j, k-1)));
    a(n) = sum(k=1, n-1, binomial(n-1, k)*T(k, 4)*T(n-k, 4));

Formula

a(n) = Sum_{k=1..n-1} binomial(n-1,k) * A000307(k) * A000307(n-k).
Showing 1-5 of 5 results.