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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A087755 Triangle read by rows: Stirling numbers of the first kind (A008275) mod 2.

Original entry on oeis.org

1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1

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Author

Philippe Deléham, Oct 02 2003

Keywords

Comments

Essentially also parity of Mitrinovic's triangles A049458, A049460, A051339, A051380.

Examples

			Triangle begins:
1
1 1
0 1 1
0 1 0 1
0 0 1 0 1
0 0 1 1 1 1
0 0 0 1 1 1 1
0 0 0 1 0 0 0 1
0 0 0 0 1 0 0 0 1
0 0 0 0 1 1 0 0 1 1
0 0 0 0 0 1 1 0 0 1 1
0 0 0 0 0 1 0 1 0 1 0 1
0 0 0 0 0 0 1 0 1 0 1 0 1
0 0 0 0 0 0 1 1 1 1 1 1 1 1
		

References

  • Das, Sajal K., Joydeep Ghosh, and Narsingh Deo. "Stirling networks: a versatile combinatorial topology for multiprocessor systems." Discrete applied mathematics 37 (1992): 119-146. See p. 122. - N. J. A. Sloane, Nov 20 2014

Programs

  • PARI
    p = 2; s=14; S1T = matrix(s,s,n,k, if(k==1,(-1)^(n-1)*(n-1)!)); for(n=2,s,for(k=2,n, S1T[n,k]=-(n-1)*S1T[n-1,k]+S1T[n-1,k-1]));
    S1TMP = matrix(s,s,n,k, S1T[n,k]%p);
    for(n=1,s,for(k=1,n,print1(S1TMP[n,k]," "));print()) /* Gerald McGarvey, Oct 17 2009 */

Formula

T(n, k) = A087748(n, k) = A008275(n, k) mod 2 = A047999([n/2], k-[(n+1)/ 2]) = T(n-2, k-2) XOR T(n-2, k-1) with T(1, 1) = T(2, 1) = T(2, 2) = 1; T(2n, k) = T(2n-1, k-1) XOR T(2n-1, k); T(2n+1, k) = T(2n, k-1). - Henry Bottomley, Dec 01 2003

Extensions

Edited and extended by Henry Bottomley, Dec 01 2003

A055924 Exponential transform of Stirling1 triangle A008275.

Original entry on oeis.org

1, -1, 2, 2, -6, 5, -6, 22, -30, 15, 24, -100, 175, -150, 52, -120, 548, -1125, 1275, -780, 203, 720, -3528, 8120, -11025, 9100, -4263, 877, -5040, 26136, -65660, 101535, -101920, 65366, -24556, 4140, 40320, -219168, 590620, -1009260, 1167348, -920808, 478842, -149040, 21147
Offset: 1

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Author

Keywords

Comments

|a(n,k)| = number of sets of permutations of {1,...,n} with k total cycles.
From David Callan, Sep 20 2007: (Start)
|a(n,k)| = Stirling1(n, k) * Bell(k) counts the above sets of permutations. To see this, recall that Stirling1(n, k) is the number of permutations of [n]={1,...,n} with k cycles and Bell(k) is the number of set partitions of [k].
Given such a permutation and set partition, write the permutation in standard cycle form (smallest entry first in each cycle and first entries decreasing left to right). For example, with n=15 and k=6, {{10}, {6, 11}, {5, 7, 15}, {3, 13, 12, 8}, {2, 14, 9}, {1, 4}} is in this standard cycle form.
Then combine cycles as specified by the partition to form a set of lists. For example, the partition 156-24-3 would yield {{10, 2, 14, 9, 1, 4}, {6, 11, 3, 13, 12, 8}, {5, 7, 15}}. The original first entries are now the record left-to-right lows.
Finally, apply to each list the well known transformation that sends # record lows to # cycles. The example yields {{4, 14, 1, 2, 10, 9}, {13, 11, 3, 6, 8, 12}, {7, 15, 5}}. This is a bijection to sets of lists (i.e. permutations) with a total of k cycles, as required. (End)

Examples

			Triangle begins:
   1;
  -1,    2;
   2,   -6,   5;
  -6,   22, -30,   15;
  24, -100, 175, -150, 52;
  ...
|a(3,2)| = 6 because (12)(3), (12)|(3), (13)(2), (13)|(2), (23)(1), (23)|(1).
		

Crossrefs

Row sums of |a(n,k)| give A000262.

Formula

E.g.f.: exp((1+x)^y-1).
a(n,k) = Stirling1(n,k) * Bell(k). - Vladeta Jovovic, Feb 01 2003

A079638 Matrix product of unsigned Lah-triangle |A008297(n,k)| and unsigned Stirling1-triangle |A008275(n,k)|.

Original entry on oeis.org

1, 3, 1, 14, 9, 1, 90, 83, 18, 1, 744, 870, 275, 30, 1, 7560, 10474, 4275, 685, 45, 1, 91440, 143892, 70924, 14805, 1435, 63, 1, 1285200, 2233356, 1274196, 324289, 41160, 2674, 84, 1, 20603520, 38769840, 24870572, 7398972, 1151409, 98280, 4578
Offset: 1

Views

Author

Vladeta Jovovic, Jan 30 2003

Keywords

Comments

Matrix product of unsigned Lah-triangle |A008297(n,k)| and Stirling1-triangle A008275(n,k) is unsigned Stirling1-triangle |A008275(n,k)|.
Also the Bell transform of A029767(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016
Essentially the same as A131222. - Peter Bala, Feb 12 2022

Examples

			Triangle begins
     1;
     3,     1;
    14,     9,    1;
    90,    83,   18,   1;
   744,   870,  275,  30,  1;
  7560, 10474, 4275, 685, 45, 1;
  ...
		

Crossrefs

Cf. A002866 (row sums), A029767 (first column), A131222.

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ..) as column 0.
    BellMatrix(n -> n!*(2^(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}]];
    B = BellMatrix[Function[n, n! (2^(n + 1) - 1)], rows = 12];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 28 2018, after Peter Luschny *)

Formula

T(n, k) = Sum_{i=k..n} |A008297(n, i)| * |A008275(i, k)|.
E.g.f.: ((1-x)/(1-2*x))^y. - Vladeta Jovovic, Nov 22 2003

A079639 Matrix product of Stirling1-triangle A008275(n,k) and unsigned Lah-triangle |A008297(n,k)|.

Original entry on oeis.org

1, 1, 1, 2, 3, 1, 4, 11, 6, 1, 14, 40, 35, 10, 1, 38, 184, 195, 85, 15, 1, 216, 840, 1204, 665, 175, 21, 1, 600, 4920, 7616, 5369, 1820, 322, 28, 1, 6240, 26616, 54116, 44016, 18669, 4284, 546, 36, 1, 9552, 197856, 392460, 383480, 191205, 54453, 9030, 870, 45, 1, 319296, 1177176, 3229776, 3449600, 2017070, 679371, 139293, 17490, 1320, 55, 1, -519312
Offset: 1

Views

Author

Vladeta Jovovic, Jan 30 2003

Keywords

Comments

Also the Bell transform of A006252(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016

Crossrefs

Cf. A006252 (first column).

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ..) as column 0.
    BellMatrix(n -> add(k!*combinat:-stirling1(n+1,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, Sum[k!*StirlingS1[n+1, k], {k, 0, n+1}]], rows];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 27 2018, after Peter Luschny *)

Formula

T(n, k) = Sum_{i=k..n} A008275(n, i) * |A008297(i, k)|.
E.g.f: (1+x)^(y/(1-log(1+x))). - Vladeta Jovovic, Nov 22 2003

A112488 Third column of triangle A112486 used for e.g.f.s of |Stirling1| = |A008275| diagonals.

Original entry on oeis.org

3, 35, 340, 3304, 33740, 367884, 4302216, 53961336, 724534272, 10386470016, 158507316864, 2567670088320, 44027031755520, 796963357981440, 15192135816261120, 304269507433658880, 6388907821376256000
Offset: 2

Views

Author

Wolfdieter Lang, Sep 12 2005

Keywords

Examples

			340 = a(4) = 6*35 + 5*26.
		

Programs

Formula

a(n) = A112486(n, 2), n>=2. a(0)=0=a(1).
a(n) = (n+2)*a(n-1) + (n+1)*A001705(n-1), n>=2, a(1):=0.

A125553 Triangle read by rows: T(n,k) = S1(n,k)*2^k, where S1(n,k) is an unsigned Stirling number of the first kind (cf. A008275) (n >= 1, 1 <= k <= n).

Original entry on oeis.org

2, 2, 4, 4, 12, 8, 12, 44, 48, 16, 48, 200, 280, 160, 32, 240, 1096, 1800, 1360, 480, 64, 1440, 7056, 12992, 11760, 5600, 1344, 128, 10080, 52272, 105056, 108304, 62720, 20608, 3584, 256, 80640, 438336, 944992, 1076544, 718368, 290304, 69888, 9216, 512
Offset: 1

Views

Author

N. J. A. Sloane, Jan 04 2007

Keywords

Comments

Row sums are factorial numbers.
T(n,k) is the number of cycle-colored n-permutations possessing exactly k cycles; two colors are available. - Steven Finch, Nov 19 2021
Subtriangle (for 1<=k<=n) of triangle given by [0,1,1,2,2,3,3,4,4,5,5,...] DELTA [2,0,2,0,2,0,2,0,2,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Jan 05 2007
Also the Bell transform of the sequence "a(n) = 2*(n+1)!/(n+1)". For the definition of the Bell transform see A264428. - Peter Luschny, Jan 27 2016

Examples

			Triangle begins:
  2
  2 4
  4 12 8
  12 44 48 16
  48 200 280 160 32
Triangle [0,1,1,2,2,3,3,...] DELTA [2,0,2,0,2,0,2,...], for 0<=k<=n, begins:
  1;
  0, 2;
  0, 2, 4;
  0, 4, 12, 8;
  0, 12, 44, 48, 16;
  0, 48, 200, 280, 160, 32;
		

Crossrefs

Programs

  • Maple
    with(combinat): T:=(n,k)->2^k*abs(stirling1(n,k)): for n from 1 to 10 do seq(T(n,k),k=1..n) od; # yields sequence in triangular form - Emeric Deutsch, Jan 05 2007
    A008275 := proc(n,k) if n = 0 and k = 0 then 1 ; elif n = 0 or k = 0 then 0 ; else A008275(n-1,k-1)-(n-1)*A008275(n-1,k) ; fi ; end ; A125553 := proc(n,k) abs(A008275(n,k)*2^k) ; end ; nmax := 10 ; for n from 1 to nmax do for k from 1 to n do printf("%d, ",A125553(n,k)) ; od ; od ; # R. J. Mathar, Jan 12 2007
    # The function BellMatrix is defined in A264428.
    # Adds (1,0,0,0, ..) as column 0.
    BellMatrix(n -> 2*(n+1)!/(n+1), 9); # Peter Luschny, Jan 27 2016
  • Mathematica
    Flatten[Table[Table[2^k Abs[StirlingS1[n,k]], {k,1,n}], {n,1,8}]] (* Geoffrey Critzer, Dec 14 2011 *)
    BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    B = BellMatrix[Function[n, 2 (n + 1)!/(n + 1)], rows = 12];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 28 2018, after Peter Luschny *)

Formula

E.g.f.: 1/(1-x)^(2y). - Geoffrey Critzer, Dec 14 2011

Extensions

More terms from R. J. Mathar, Jan 12 2007

A104416 Triangle, read by rows, where T(n,k) = A008275(k+1,n-k+1) are Stirling numbers of the first kind.

Original entry on oeis.org

1, -1, 1, 0, -3, 1, 0, 2, -6, 1, 0, 0, 11, -10, 1, 0, 0, -6, 35, -15, 1, 0, 0, 0, -50, 85, -21, 1, 0, 0, 0, 24, -225, 175, -28, 1, 0, 0, 0, 0, 274, -735, 322, -36, 1, 0, 0, 0, 0, -120, 1624, -1960, 546, -45, 1, 0, 0, 0, 0, 0, -1764, 6769, -4536, 870, -55, 1, 0, 0, 0, 0, 0, 720, -13132, 22449, -9450, 1320, -66, 1
Offset: 0

Views

Author

Paul D. Hanna, Mar 06 2005

Keywords

Comments

The matrix inverse forms A104417, in which column 0 equals A082161.

Examples

			A(x,y) = (1-x) + x*y*(1-x)*(1-2*x) + x^2*y^2*(1-x)*(1-2*x)*(1-3*x) + x^3*y^3*(1-x)*(1-2*x)*(1-3*x)*(1-4*x) + ...
Rows begin:
  1;
  -1,1;
  0,-3,1;
  0,2,-6,1;
  0,0,11,-10,1;
  0,0,-6,35,-15,1;
  0,0,0,-50,85,-21,1;
  0,0,0,24,-225,175,-28,1;
  0,0,0,0,274,-735,322,-36,1;
  0,0,0,0,-120,1624,-1960,546,-45,1;
  ...
		

Crossrefs

Programs

  • PARI
    {T(n,k)=local(X=x+x*O(x^n),Y=y+y*O(y^k)); polcoeff(polcoeff(sum(i=0,n,X^i*Y^i*prod(j=1,i+1,1-j*X)),n,x),k,y)}

Formula

G.f.: A(x, y) = Sum_{n>=0} x^n*y^n*Product_{k=1..n+1} (1-k*x).

A104417 Triangle, read by rows, equal to the matrix inverse of A104416, where A104416(n,k) = A008275(k+1,n-k+1) (Stirling numbers of the first kind).

Original entry on oeis.org

1, 1, 1, 3, 3, 1, 16, 16, 6, 1, 127, 127, 49, 10, 1, 1363, 1363, 531, 115, 15, 1, 18628, 18628, 7286, 1615, 230, 21, 1, 311250, 311250, 121964, 27321, 4040, 413, 28, 1, 6173791, 6173791, 2421471, 545311, 82131, 8841, 686, 36, 1, 142190703, 142190703
Offset: 0

Views

Author

Paul D. Hanna, Mar 06 2005

Keywords

Comments

Column 0 and column 1 contain A082161.

Examples

			Column 0 forms A082161 that satisfies:
1 = (1-x) + 1*x*(1-x)(1-2x) + 3*x^2*(1-x)(1-2x)(1-3x) +
+ 16*x^3*(1-x)(1-2x)(1-3x)(1-4x) + ...
+ A082161(n+1)*x^n*(1-x)(1-2x)(1-3x)*..*(1-(n+1)*x) + ...
this g.f. can be derived from the matrix inverse, A104416.
Rows begin:
1;
1,1;
3,3,1;
16,16,6,1;
127,127,49,10,1;
1363,1363,531,115,15,1;
18628,18628,7286,1615,230,21,1;
311250,311250,121964,27321,4040,413,28,1; ...
		

Crossrefs

Programs

  • PARI
    
    				

A112489 Fourth column of triangle A112486 used for e.g.f.s of |Stirling1|=|A008275| diagonals.

Original entry on oeis.org

15, 315, 4900, 70532, 1008980, 14777620, 224655816, 3568061640, 59371808496, 1035987707664, 18953413075584, 363290743698048, 7287692926408704, 152811506045431296, 3344880701417587200, 76327884878442508800
Offset: 3

Views

Author

Wolfdieter Lang, Sep 12 2005

Keywords

Examples

			4900 = a(5) = 8*315 + 7*340.
		

Formula

a(n)= A112486(n, 3), n>=3. a(0)=a(1)=a(2)=0.
a(n)= (n+3)*a(n-1) + (n+2)*A112488(n-1), n>=3, a(2):=0.

A112490 Fifth column of triangle A112486 used for e.g.f.s of |Stirling1|=|A008275| diagonals.

Original entry on oeis.org

105, 3465, 78750, 1571570, 29957620, 566780500, 10855452608, 212784652080, 4295131560720, 89593039854864, 1934882739672480, 43302005440341984, 1004506274408605056, 24150861883489332096, 601561456166534637312
Offset: 4

Views

Author

Wolfdieter Lang, Sep 12 2005

Keywords

Examples

			78750 = a(6) = 10*3465 + 9*4900.
		

Formula

a(n)= A112486(n, 4), n>=4. a(0), ..., a(3) = 0.
a(n)= (n+4)*a(n-1) + (n+3)* A112489(n-1), n>=4, a(3):=0.
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