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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A069138 Triangle formed by multiplying Stirling numbers of 2nd kind S2(n,m) (A008277) by m+1.

Original entry on oeis.org

2, 2, 3, 2, 9, 4, 2, 21, 24, 5, 2, 45, 100, 50, 6, 2, 93, 360, 325, 90, 7, 2, 189, 1204, 1750, 840, 147, 8, 2, 381, 3864, 8505, 6300, 1862, 224, 9, 2, 765, 12100, 38850, 41706, 18522, 3696, 324, 10, 2, 1533, 37320, 170525, 255150, 159789, 47040, 6750, 450, 11
Offset: 1

Views

Author

N. J. A. Sloane, Apr 10 2002

Keywords

Comments

The number of rhyme schemes for a stanza of n+1 lines with m rhyming syllables in its first n lines.

Examples

			Triangle begins:
  2;
  2,  3;
  2,  9,   4;
  2, 21,  24,  5;
  2, 45, 100, 50, 6;
  ...
		

References

Crossrefs

Row sums give Bell numbers A000110.
Cf. A360174 (Stirling1 counterpart), A360205 (Lah counterpart).

Programs

  • PARI
    T(n, m) = stirling(n, m, 2)*(m+1);
    tabl(nn) = for(n=1, nn, for (k=1, n, print1(T(n, m), ", ")); print); \\ Michel Marcus, Sep 21 2017

Formula

T(n, m) = (m+1)*S2(n, m).

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jul 01 2002

A088729 Matrix product of Stirling2-triangle A008277(n,k) and unsigned Lah-triangle |A008297(n,k)|.

Original entry on oeis.org

1, 3, 1, 13, 9, 1, 75, 79, 18, 1, 541, 765, 265, 30, 1, 4683, 8311, 3870, 665, 45, 1, 47293, 100989, 59101, 13650, 1400, 63, 1, 545835, 1362439, 960498, 278901, 38430, 2618, 84, 1, 7087261, 20246445, 16700545, 5844510, 1012431, 92610, 4494, 108, 1
Offset: 1

Views

Author

Vladeta Jovovic, Nov 22 2003

Keywords

Comments

Also the Bell transform of A000670(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016
Also the number of k-dimensional flats of the n-dimensional Catalan arrangement. - Shuhei Tsujie, May 05 2019

Crossrefs

Cf. A000670(first column), A075729(row sums).

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ..) as column 0.
    BellMatrix(n -> add(combinat:-eulerian1(n+1, k)*2^k, k=0..n+1), 9); # Peter Luschny, Jan 26 2016
  • Mathematica
    BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    rows = 12;
    B = BellMatrix[Function[n, HurwitzLerchPhi[1/2, -n-1, 0]/2], rows];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 27 2018, after Peter Luschny *)

Formula

E.g.f.: exp((exp(x)-1)*y/(2-exp(x))).

A088814 Matrix product of unsigned Lah-triangle |A008297(n,k)| and Stirling2-triangle A008277(n,k).

Original entry on oeis.org

1, 3, 1, 13, 9, 1, 73, 79, 18, 1, 501, 755, 265, 30, 1, 4051, 7981, 3840, 665, 45, 1, 37633, 93135, 57631, 13580, 1400, 63, 1, 394353, 1192591, 911582, 274141, 38290, 2618, 84, 1, 4596553, 16645431, 15285313, 5633922, 999831, 92358, 4494, 108, 1, 58941091
Offset: 1

Views

Author

Vladeta Jovovic, Nov 22 2003

Keywords

Comments

Also the Bell transform of A000262(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016

Crossrefs

Cf. A000262(first column), A084357(row sums).

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ..) as column 0.
    BellMatrix(n -> simplify(hypergeom([-n,-n-1],[],1)), 9); # Peter Luschny, Jan 26 2016
  • Mathematica
    BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    rows = 12;
    B = BellMatrix[Function[n, Sum[BellY[n+1, k, Range[n+1]!], {k, 0, n+1}]], rows];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 28 2018, after Peter Luschny_ *)

Formula

E.g.f.: exp(y*(exp(x/(1-x))-1)).

A227450 Triangular array read by rows. T(n,k) = A008277(n,k)*2^k; n >= 1, 1 <= k <= n.

Original entry on oeis.org

2, 2, 4, 2, 12, 8, 2, 28, 48, 16, 2, 60, 200, 160, 32, 2, 124, 720, 1040, 480, 64, 2, 252, 2408, 5600, 4480, 1344, 128, 2, 508, 7728, 27216, 33600, 17024, 3584, 256, 2, 1020, 24200, 124320, 222432, 169344, 59136, 9216, 512, 2, 2044, 74640, 545680, 1360800, 1460928, 752640, 192000, 23040, 1024
Offset: 1

Views

Author

Geoffrey Critzer, Sep 22 2013

Keywords

Comments

T(n,k) is the number of ways to separate {1,2,...,n} into 2 ordered subsets S,T so that the union of S and T = {1,2,...,n} then partition each subset so that the total number of blocks over both subsets is equal to k.
Triangle T(n,k), 1<=k<=n, read by rows, given by (0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, ...) DELTA (2, 0, 2, 0, 2, 0, 2, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Sep 23 2013
Also the Bell transform of the constant sequence "a(n) = 2". For the definition of the Bell transform see A264428. - Peter Luschny, Jan 29 2016

Examples

			2,
2, 4,
2, 12, 8,
2, 28, 48, 16,
2, 60, 200, 160, 32,
2, 124, 720, 1040, 480, 64
		

Crossrefs

Cf. A008277.

Programs

  • Mathematica
    nn=8; a=Exp[x]-1; Map[Select[#, #>0&]&, Drop[Range[0,nn]! CoefficientList[Series[Exp[y a]^2, {x,0,nn}], {x,y}], 1]]//Grid
    (* or *)
    Flatten[Table[StirlingS2[n,k]*2^k,{n,1,10},{k,1,n}]] (* Indranil Ghosh, Feb 22 2017 *)
    BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    B = BellMatrix[2&, rows = 12];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 28 2018, after Peter Luschny *)
  • Python
    # The function BellMatrix is defined in A264428.
    # Adds (1,0,0,0, ..) as column 0.
    BellMatrix(lambda n: 2, 9); # Peter Luschny, Jan 29 2016

Formula

E.g.f.: A(x,y)^2 where A(x,y) is the e.g.f. for A008277.

A325503 Heinz number of row n of the triangle of Stirling numbers of the second kind A008277.

Original entry on oeis.org

2, 4, 20, 884, 528844, 3460086044, 340672148731996, 477782556719729075524, 11694209380474301218263758996, 4967476846044415922850025924897606724, 43298471669920632729336800855543564573041217668, 7790810575556906457316064931238939360882160372451591124244
Offset: 1

Views

Author

Gus Wiseman, May 07 2019

Keywords

Comments

The Heinz number of a positive integer sequence (y_1,...,y_k) is prime(y_1)*...*prime(y_k).

Examples

			The sequence of terms together with their prime indices begins:
                              2: {1}
                              4: {1,1}
                             20: {1,1,3}
                            884: {1,1,6,7}
                         528844: {1,1,10,15,25}
                     3460086044: {1,1,15,31,65,90}
                340672148731996: {1,1,21,63,140,301,350}
          477782556719729075524: {1,1,28,127,266,966,1050,1701}
  11694209380474301218263758996: {1,1,36,255,462,2646,3025,6951,7770}
		

Crossrefs

Programs

  • Mathematica
    Times@@@Table[Prime[StirlingS2[n,k]],{n,1,10},{k,1,n}]

Formula

a(n) = Product_{i = 1..n} prime(A008277(n,i)).
A061395(a(n)) = A002870(n).
A056239(a(n)) = A000110(n).

A348649 Odd numbers in the triangle of Stirling numbers of the second kind (A008277).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 7, 1, 1, 15, 25, 1, 1, 31, 65, 15, 1, 1, 63, 301, 21, 1, 1, 127, 1701, 1, 1, 255, 3025, 6951, 1, 1, 511, 34105, 42525, 22827, 45, 1, 1, 1023, 28501, 179487, 63987, 1155, 55, 1, 1, 2047, 611501, 159027, 22275, 1705, 1, 1, 4095, 261625, 7508501, 39325, 2431, 1
Offset: 1

Views

Author

Rémy Sigrist, Oct 27 2021

Keywords

Comments

We take the odd values in A008277, as they appear, with duplicates.
For any n >= 1, the n-th row has A007306(n) terms.

Examples

			As an irregular table, the first rows are:
     1:    1;
     2:    1, 1;
     3:    1, 3, 1;
     4:    1, 7, 1;
     5:    1, 15, 25, 1;
     6:    1, 31, 65, 15, 1;
     7:    1, 63, 301, 21, 1;
     8:    1, 127, 1701, 1;
     9:    1, 255, 3025, 6951, 1;
    10:    1, 511, 34105, 42525, 22827, 45, 1;
    11:    1, 1023, 28501, 179487, 63987, 1155, 55, 1;
    ...
		

Crossrefs

See A014421, A014428, A014450, A014459 for similar sequences.
Cf. A007306, A008277, A348650 (even numbers).

Programs

  • PARI
    row(n) = select(v -> v%2==1, vector(n, k, stirling(n, k, 2)))

A348650 Even numbers in the triangle of Stirling numbers of the second kind (A008277).

Original entry on oeis.org

6, 10, 90, 350, 140, 966, 1050, 266, 28, 7770, 2646, 462, 36, 9330, 5880, 750, 145750, 246730, 11880, 86526, 1379400, 1323652, 627396, 66, 2532530, 9321312, 5715424, 1899612, 359502, 78, 788970, 49329280, 20912320, 5135130, 752752, 66066, 42355950, 210766920
Offset: 4

Views

Author

Rémy Sigrist, Oct 27 2021

Keywords

Comments

We take the even values in A008277, as they appear, with duplicates.
For any n >= 4, the n-th row has n - A007306(n) terms.

Examples

			As an irregular table, the first rows are:
     4:   6;
     5:   10;
     6:   90;
     7:   350, 140;
     8:   966, 1050, 266, 28;
     9:   7770, 2646, 462, 36;
    10:   9330, 5880, 750;
    11:   145750, 246730, 11880;
    12:   86526, 1379400, 1323652, 627396, 66;
    13:   2532530, 9321312, 5715424, 1899612, 359502, 78;
    14:   788970, 49329280, 20912320, 5135130, 752752, 66066;
    ...
		

Crossrefs

Cf. A007306, A008277, A348649 (odd numbers).

Programs

  • PARI
    row(n) = select(v -> v%2==0, vector(n, k, stirling(n, k, 2)))

A091046 Stirling transform of first differences of Bell numbers (A005493), if offset zero: a(n) = Sum_{k=1..n} A008277(n,k)*A005493(k).

Original entry on oeis.org

1, 4, 20, 119, 817, 6338, 54707, 519184, 5366097, 59934937, 718748131, 9203953921, 125268224954, 1804750726306, 27426230051634, 438260834123607, 7343677070172330, 128716143768613600, 2354633702684629141, 44865189679858465163, 888784065003104357924
Offset: 1

Views

Author

Karol A. Penson, Dec 15 2003

Keywords

Comments

Equals A039810 * [1,2,3,...], i.e., the square of the Stirling2 triangle and the natural number vector. - Gary W. Adamson, Jan 31 2008
From Mark Wildon, Nov 01 2022: (Start)
a(n) is the number of pairs (P, P') where P' is a set partition of {1,...,n}, P is a set partition of {1,...,P} refining P, and one part of P' is distinguished.
For example, for n=2 the 4 set partition pairs for n=2 are ({{1,2}},{{1,2}*}), ({{1},{2}},{{1,2}}*), ({{1},{2}},{{1}*,{2}}), ({{1},{2}},{{1},{2}*}), where the distinguished part of the coarser partition is marked *
a(n) is the inner product in the character ring of the symmetric group S_{mn} of the characters pi^n and phi_n Ind_{S_m wr S_n}^{S_{mn}}, where pi(g) = |Fix g| is the permutation character of the natural representation of S_{mn} and phi_n is the character of the wreath product S_m wr S_n obtained by inflating the character chi^{(n-1,1)} of S_n to S_m wr S_n. (End)

Crossrefs

Programs

  • Maple
    s:= proc(n) option remember; expand(`if`(n=0, 1,
          x*add(s(n-j)*binomial(n-1, j-1), j=1..n)))
        end:
    S:= proc(n, k) option remember; coeff(s(n), x, k) end:
    b:= proc(n, k) option remember; `if`(k=0, n,
          add(S(n, j)*b(j, k-1), j=0..n))
        end:
    a:= n-> b(n, 2):
    seq(a(n), n=1..23);  # Alois P. Heinz, Aug 24 2021
  • Mathematica
    len = 23;
    Array[StirlingS2, {len, len}].Differences[Array[BellB, len+1]] (* Jean-François Alcover, Apr 25 2022 *)

Formula

E.g.f.: (exp(exp(x)-1)-1)*exp(exp(exp(x)-1)-1).
Representation as an infinite sum (Dobinski-type relation): a(n) = exp(exp(-1)-1)*Sum(p^n*((Sum((Stirling2(p+1, k) - Stirling2(p, k))*exp(-k), k=1..p) + exp(-(p+1)))/p!), p>=1), n = 1, 2, ....

A112339 Triangle read by rows of numbers b_{n,k}, n >= 2, 1 <= k < n such that (1/(1-q*t))*Product_{n,k} 1/(1 - q^n*t^k)^b_{n,k} = Sum_{i,j>=1} S_{i,j} q^i*t^j where S_{i,j} are entries in the table A008277 (the inverse Euler transformation of the table of Stirling numbers of the second kind).

Original entry on oeis.org

1, 1, 2, 1, 5, 3, 1, 13, 16, 4, 1, 28, 67, 34, 5, 1, 60, 249, 229, 65, 6, 1, 123, 853, 1265, 609, 107, 7, 1, 251, 2787, 6325, 4696, 1376, 168, 8, 1, 506, 8840, 29484, 31947, 14068, 2772, 244, 9, 1, 1018, 27503, 131402, 199766, 124859, 36252, 5118, 345, 10
Offset: 2

Views

Author

Mike Zabrocki, Sep 05 2005

Keywords

Comments

Row sums equal to A085686 second column = A084174 - 1.

Examples

			Triangle begins:
  1;
  1,  2;
  1,  5,  3;
  1, 13, 16,  4;
  ...
		

Crossrefs

Programs

  • Maple
    EULERitable:=proc(tbl) local ser,out,i,j,tmp; ser:=1+add(add(q^i*t^j*tbl[i][j], j=1..nops(tbl[i])), i=1..nops(tbl)); out:=[]; for i from 1 to nops(tbl) do tmp:=coeff(ser,q,i); ser:=expand(ser*mul(add((-q^i*t^j)^k*choose(abs(coeff(tmp,t,j)),k),k=0..nops(tbl)/i), j = 1..degree(tmp,t))); ser:=subs({seq(q^j=0,j=nops(tbl)+1..degree(ser,q))},ser); out:=[op(out),[seq(abs(coeff(tmp,t,j)), j=1..degree(tmp,t))]]; end do; out; end: EULERitable([seq([seq(combinat[stirling2](n,k),k=1..n)],n=1..11)]);

A137649 Triangle read by rows, A000012 * A008277.

Original entry on oeis.org

1, 2, 1, 3, 4, 1, 4, 11, 7, 1, 5, 26, 32, 11, 1, 6, 57, 122, 76, 16, 1, 7, 120, 423, 426, 156, 22, 1, 8, 247, 1389, 2127, 1206, 288, 29, 1, 9, 502, 4414, 9897, 8157, 2934, 491, 37, 1, 10, 1013, 13744, 44002, 50682, 25761, 6371, 787, 46, 1
Offset: 1

Views

Author

Gary W. Adamson, Feb 01 2008

Keywords

Comments

Row sums = A024716: (1, 3, 8, 23, 75, 278, ...).

Examples

			First few rows of the triangle:
  1;
  2,   1;
  3,   4,   1;
  4,  11,   7,   1;
  5,  26,  32,  11,   1;
  6,  57, 122,  76,  16,  1;
  7, 120, 423, 426, 156, 22, 1;
  ...
Row 4 = (4, 11, 7, 1) = partial column sums of the first 4 rows of A008277:
  1;
  1, 1;
  1, 3, 1;
  1, 7, 6, 1;
  ...
		

Crossrefs

Formula

A000012 * A008277 (Stirling2 triangle) as infinite lower triangular matrices. Partial column sums of A008277.
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