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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A059098 Triangle read by rows. T(n, k) = Sum_{i=0..n} Stirling2(n, i)*Product_{j=1..k} (i - j + 1) for 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 2, 3, 2, 5, 10, 12, 6, 15, 37, 62, 60, 24, 52, 151, 320, 450, 360, 120, 203, 674, 1712, 3120, 3720, 2520, 720, 877, 3263, 9604, 21336, 33600, 34440, 20160, 5040, 4140, 17007, 56674, 147756, 287784, 394800, 352800, 181440, 40320, 21147, 94828
Offset: 0

Views

Author

Vladeta Jovovic, Jan 02 2001

Keywords

Comments

The transpose of this lower unitriangular array is the U factor in the LU decomposition of the Hankel matrix (Bell(i+j-2))A000110(n).%20The%20L%20factor%20is%20A049020%20(see%20Chamberland,%20p.%201672).%20-%20_Peter%20Bala">i,j >= 1, where Bell(n) = A000110(n). The L factor is A049020 (see Chamberland, p. 1672). - _Peter Bala, Oct 15 2023

Examples

			Triangle begins:
  [0] [ 1]
  [1] [ 1,    1]
  [2] [ 2,    3,    2]
  [3] [ 5,   10,   12,    6]
  [4] [15,   37,   62,   60,   24]
  [5] [52,  151,  320,  450,  360,  120]
  [6] [203, 674, 1712, 3120, 3720, 2520, 720]
  ...;
E.g.f. for T(n, 2) = (exp(x)-1)^2*(exp(exp(x)-1)) = x^2 + 2*x^3 + 31/12*x^4 + 8/3*x^5 + 107/45*x^6 + 343/180*x^7 + 28337/20160*x^8 + 349/360*x^9 + ...;
E.g.f. for T(n, 3) = (exp(x)-1)^3*(exp(exp(x)-1)) = x^3 + 5/2*x^4 + 15/4*x^5 + 13/3*x^6 + 127/30*x^7 + 1759/480*x^8 + 34961/12096*x^9 + ...
		

Crossrefs

Cf. A000110(n) = T(n,0), A005493(n) = T(n,1), A059099 (row sums).

Programs

  • Maple
    T := proc(n, k) option remember; `if`(k < 0 or k > n, 0,
          `if`(n = 0, 1, k*T(n-1, k-1) + (k+1)*T(n-1, k) + T(n-1, k+1)))
        end:
    seq(print(seq(T(n, k), k = 0..n)), n = 0..15); # Peter Bala, Oct 15 2023

Formula

E.g.f. for T(n, k): (exp(x)-1)^k*(exp(exp(x)-1)).
n-th row is M^n*[1,0,0,0,...], where M is a tridiagonal matrix with all 1's in the superdiagonal, (1,2,3,...) in the main and subdiagonals; and the rest zeros. - Gary W. Adamson, Jun 23 2011
T(n, k) = k!*A049020(n, k). - R. J. Mathar, May 17 2016
T(n, k) = Sum_{j=0..k} (-1)^(k-j)*A046716(k, k-j)*Bell(n + j). - Peter Luschny, Dec 06 2023

A095675 Triangle read by rows, formed from product of Aitken's (or Bell's) triangle (A011971) and Pascal's triangle (A007318).

Original entry on oeis.org

1, 3, 2, 10, 13, 5, 37, 72, 55, 15, 151, 393, 450, 245, 52, 674, 2202, 3365, 2748, 1166, 203, 3263, 12850, 24582, 26781, 17048, 5936, 877, 17007, 78488, 180477, 245971, 208856, 109107, 32243, 4140, 94828, 502327, 1349900, 2209695, 2346559, 1634998
Offset: 0

Views

Author

N. J. A. Sloane, based on a suggestion from Gary W. Adamson, Jun 22 2004

Keywords

Comments

These triangles are to be thought of as infinite lower-triangular matrices.

Examples

			Triangle begins:
1
3 2
10 13 5
37 72 55 15
151 393 450 245 52
		

Crossrefs

Cf. A007318, A011971, A095674. Row sums give A095676. First column is A005493.

Programs

  • Mathematica
    a[0, 0] = 1; a[n_, 0] := a[n - 1, n - 1]; a[n_, k_] := a[n, k] = If[k < n + 1, a[n, k - 1] + a[n - 1, k - 1], 0]; p[n_, r_] := If[r <= n + 1, Binomial[n, r], 0]; am = Table[ a[n, r], {n, 0, 9}, {r, 0, 9}]; pm = Table[p[n, r], {n, 0, 9}, {r, 0, 9}]; t = Flatten[am.pm]; Delete[ t, Position[t, 0]] (* Robert G. Wilson v, Jul 12 2004 *)

Extensions

More terms from Robert G. Wilson v, Jul 13 2004

A125098 Values occurring in A123895.

Original entry on oeis.org

0, 1, 10, 11, 12, 100, 101, 102, 110, 111, 112, 120, 121, 122, 123, 1000, 1001, 1002, 1010, 1011, 1012, 1020, 1021, 1022, 1023, 1100, 1101, 1102, 1110, 1111, 1112, 1120, 1121, 1122, 1123, 1200, 1201, 1202, 1203, 1210, 1211, 1212, 1213, 1220, 1221, 1222
Offset: 0

Views

Author

Keywords

Comments

Also, numbers n such that A123895(n) = n. Each digit is either 0, has occurred before, or is one more than the largest preceding digit. The number of k-digit numbers in this sequence is A005493(k-1) for 2<=k<=9. The initial 0 prevents a match for k=1; later values fall short because there are no digits beyond 9 available in decimal.

Crossrefs

Programs

  • Maple
    bag := {} ;
    for i from 0 to 99999 do
        bag := bag union {A123895(i)} ;
    end do:
    sort(convert(bag,list)) ; # R. J. Mathar, Dec 10 2015
  • Mathematica
    f[n_] := Block[{d = Prepend[IntegerDigits@ n, 0], a, b, w}, b = DeleteDuplicates@ d; a = Range[0, Length@ b]; w = FromDigits@ Flatten[Part[a, FirstPosition[b, #]] & /@ d]; w]; Union@ Table[f@n, {n, 0, 10^4}] (* Michael De Vlieger, Dec 09 2015, Version 10 *)

A191099 5th differences of Bell numbers.

Original entry on oeis.org

11, 52, 255, 1335, 7432, 43833, 272947, 1788850, 12303997, 88586135, 666047210, 5218287687, 42518759887, 359651145332, 3152929344235, 28603584325827, 268159523175744, 2594608337127709, 25878365376280647, 265770087291261082, 2807571511844891521
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    Differences[BellB[Range[0, 50]], 5]

A225591 a(n) = B(n+3) - 6*B(n+2) + 8*B(n+1)*B(n+1) - B(n), where the B(i) are Bell numbers (A000110).

Original entry on oeis.org

0, 16, 160, 1686, 21276, 328498, 6149136, 137105016, 3577543452, 107601726030, 3683660206080, 142035221781402, 6113719409724768, 291540411275223912, 15300594717301253800, 878667035554110785662, 54932693182800769213284
Offset: 0

Views

Author

Michel Marcus, Jun 19 2013

Keywords

Crossrefs

Cf. A005493, A226506 (see Prop 3.1 (i) in Chern et al. link).

Programs

  • Magma
    [Bell(n+3)-6*Bell(n+2)+8*Bell(n+1)*Bell(n+1)-Bell(n): n in [0..20]]; // Vincenzo Librandi, Jul 16 2013
  • Mathematica
    Table[BellB[n+3] - 6 BellB[n+2] + 8 BellB[n+1] BellB[n+1] - BellB[n], {n, 0, 20}] (* Vincenzo Librandi, Jul 16 2013 *)
    #[[4]]-6#[[3]]+8#[[2]]^2-#[[1]]&/@Partition[BellB[Range[0,20]],4,1] (* Harvey P. Dale, Nov 01 2016 *)
  • PARI
    B(n) = if (n<=1, return (1), return (sum(i=0, n-1, binomial(n-1, i)*B(n-1-i))))
    a(n) = B(n+3) - 6*B(n+2) + 8*B(n+1)*B(n+1) - B(n)
    

A226506 a(n) = B(n+2)-3*B(n+1)+B(n), where B(i) are the Bell numbers A000110.

Original entry on oeis.org

0, 0, 2, 12, 62, 320, 1712, 9604, 56674, 351792, 2293862, 15682216, 112179608, 837905016, 6522165834, 52807401908, 443962338894, 3869376656384, 34908008426360, 325530083655692, 3133830448212442, 31106728455899128, 318009567467999574, 3344865730200667832, 36161434396223563504
Offset: 0

Views

Author

N. J. A. Sloane, Jun 10 2013

Keywords

Crossrefs

Cf. A000110.
Cf. A005493, A225591 (see Prop 3.1 (i) in Chern et al. link).

Programs

  • Magma
    [Bell(n+2)-3*Bell(n+1)+Bell(n): n in [0..30]]; // Vincenzo Librandi, Jul 16 2013
  • Mathematica
    Table[BellB[n+2] - 3 BellB[n+1] + BellB[n], {n, 0, 30}] (* Vincenzo Librandi, Jul 16 2013 *)
    #[[3]]-3#[[2]]+#[[1]]&/@Partition[BellB[Range[0,30]],3,1] (* Harvey P. Dale, Aug 26 2021 *)

A269952 Triangle read by rows, T(n,k) = Sum_{j=0..n} (-1)^(n-j)*C(-j,-n)*S2(j,k), S2 the Stirling set numbers A048993, for n>=0 and 0<=k<=n.

Original entry on oeis.org

1, 0, 1, 0, 2, 1, 0, 4, 5, 1, 0, 8, 19, 9, 1, 0, 16, 65, 55, 14, 1, 0, 32, 211, 285, 125, 20, 1, 0, 64, 665, 1351, 910, 245, 27, 1, 0, 128, 2059, 6069, 5901, 2380, 434, 35, 1, 0, 256, 6305, 26335, 35574, 20181, 5418, 714, 44, 1
Offset: 0

Views

Author

Peter Luschny, Apr 10 2016

Keywords

Examples

			1,
0, 1,
0, 2, 1,
0, 4, 5, 1,
0, 8, 19, 9, 1,
0, 16, 65, 55, 14, 1,
0, 32, 211, 285, 125, 20, 1,
0, 64, 665, 1351, 910, 245, 27, 1.
		

Crossrefs

Variant: A143494 (the main entry for this triangle).
A005493 (row sums), A074051 (alt. row sums), A000079 (col. 1), A001047 (col. 2),
A016269 (col. 3), A025211 (col. 4), A000096 (diag. n,n-1), A215862 (diag. n,n-2),
A049444, A136124, A143491 (matrix inverse).

Programs

  • Maple
    A269952 := (n,k) -> Stirling2(n+1, k+1) - Stirling2(n, k+1):
    seq(seq(A269952(n,k), k=0..n), n=0..9);
  • Mathematica
    Flatten[ Table[ Sum[(-1)^(n-j) Binomial[-j,-n] StirlingS2[j,k], {j,0,n}], {n,0,9}, {k,0,n}]]

Formula

T(n, k) = S2(n+1, k+1) - S2(n, k+1).

A339030 T(n, k) = Sum_{p in P(n, k)} card(p), where P(n, k) is the set of set partitions of {1,2,...,n} where the largest block has size k and card(p) is the number of blocks of p. Triangle T(n, k) for 0 <= k <= n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 2, 1, 0, 3, 6, 1, 0, 4, 24, 8, 1, 0, 5, 85, 50, 10, 1, 0, 6, 300, 280, 75, 12, 1, 0, 7, 1071, 1540, 525, 105, 14, 1, 0, 8, 3976, 8456, 3570, 840, 140, 16, 1, 0, 9, 15219, 47208, 24381, 6552, 1260, 180, 18, 1
Offset: 0

Views

Author

Peter Luschny, Nov 22 2020

Keywords

Examples

			Triangle starts:
0: [1]
1: [0, 1]
2: [0, 2, 1]
3: [0, 3, 6,     1]
4: [0, 4, 24,    8,     1]
5: [0, 5, 85,    50,    10,    1]
6: [0, 6, 300,   280,   75,    12,   1]
7: [0, 7, 1071,  1540,  525,   105,  14,   1]
8: [0, 8, 3976,  8456,  3570,  840,  140,  16,  1]
9: [0, 9, 15219, 47208, 24381, 6552, 1260, 180, 18, 1]
.
T(4,0) = 0  = 0*card({})
T(4,1) = 4  = 4*card({1|2|3|4}).
T(4,2) = 24 = 3*card({12|3|4, 13|2|4, 1|23|4, 14|2|3, 1|24|3, 1|2|34})
            + 2*card({12|34, 13|24, 14|23}).
T(4,3) = 8  = 2*card({123|4, 124|3, 134|2, 1|234}).
T(4,4) = 1  = 1*card({1234}).
.
Seen as the projection of a 2-dimensional statistic this is, for n = 6:
[  0   0    0     0     0    0   0]
[  0   0    0     0     0    0   6]
[  0   0    0    45   180   75   0]
[  0   0   20   180    80    0   0]
[  0   0   30    45     0    0   0]
[  0   0   12     0     0    0   0]
[  0   1    0     0     0    0   0]
The row sum projection gives row 6 of this triangle, and the column sum projection gives [0, 1, 62, 270, 260, 75, 6], which appears in a decapitated version as row 5 in A321331.
		

Crossrefs

Cf. A005493 with 1 prepended are the row sums.

Programs

  • SageMath
    def A339030Row(n):
        if n == 0: return [1]
        M = matrix(n + 1)
        for k in (1..n):
            for p in SetPartitions(n):
                if p.max_block_size() == k:
                    M[k, len(p)] += p.cardinality()
        return [sum(M[k, j] for j in (0..n)) for k in (0..n)]
    for n in (0..9): print(A339030Row(n))

A346842 E.g.f.: exp(exp(x) - 1) * (exp(x) - 1)^3 / 3!.

Original entry on oeis.org

1, 10, 75, 520, 3556, 24626, 174805, 1279240, 9677151, 75750752, 613656836, 5142797660, 44557627661, 398786697398, 3683575764083, 35084121263136, 344242894197456, 3476490965903174, 36104281709286841, 385257741260565844, 4220537246457019687, 47432055430482106880
Offset: 3

Views

Author

Ilya Gutkovskiy, Aug 05 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, m) option remember;
         `if`(n=0, binomial(m, 3), m*b(n-1, m)+b(n-1, m+1))
        end:
    a:= n-> b(n, 0):
    seq(a(n), n=3..24);  # Alois P. Heinz, Aug 05 2021
  • Mathematica
    nmax = 24; CoefficientList[Series[Exp[Exp[x] - 1] (Exp[x] - 1)^3/3!, {x, 0, nmax}], x] Range[0, nmax]! // Drop[#, 3] &
    Table[Sum[StirlingS2[n, k] Binomial[k, 3], {k, 0, n}], {n, 3, 24}]
    Table[Sum[Binomial[n, k] StirlingS2[k, 3] BellB[n - k], {k, 0, n}], {n, 3, 24}]
    Table[(BellB[n+3] - 6*BellB[n+2] + 8*BellB[n+1] - BellB[n])/6, {n, 3, 24}] (* Vaclav Kotesovec, Aug 06 2021 *)
  • PARI
    my(x='x+O('x^25)); Vec(serlaplace(exp(exp(x)-1)*(exp(x)-1)^3/3!)) \\ Michel Marcus, Aug 06 2021

Formula

a(n) = Sum_{k=0..n} Stirling2(n,k) * binomial(k,3).
a(n) = Sum_{k=0..n} binomial(n,k) * Stirling2(k,3) * Bell(n-k).
a(n) = (Bell(n+3) - 6*Bell(n+2) + 8*Bell(n+1) - Bell(n))/6. - Vaclav Kotesovec, Aug 06 2021
a(n) ~ exp(-1 - n + n/LambertW(n)) * (n - LambertW(n))^3 * n^n / (6 * sqrt(1 + LambertW(n)) * LambertW(n)^(n+3)). - Vaclav Kotesovec, Jun 28 2022

A346843 E.g.f.: exp(exp(x) - 1) * (exp(x) - 1)^4 / 4!.

Original entry on oeis.org

1, 15, 155, 1400, 11991, 101031, 853315, 7300260, 63641006, 567304452, 5181338526, 48538121450, 466611951261, 4603782469653, 46613101232933, 484188586821376, 5157850655391981, 56321812548867229, 630125374420189131, 7219368394888423554, 84658119388335562972
Offset: 4

Views

Author

Ilya Gutkovskiy, Aug 05 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, m) option remember;
         `if`(n=0, binomial(m, 4), m*b(n-1, m)+b(n-1, m+1))
        end:
    a:= n-> b(n, 0):
    seq(a(n), n=4..24);  # Alois P. Heinz, Aug 05 2021
  • Mathematica
    nmax = 24; CoefficientList[Series[Exp[Exp[x] - 1] (Exp[x] - 1)^4/4!, {x, 0, nmax}], x] Range[0, nmax]! // Drop[#, 4] &
    Table[Sum[StirlingS2[n, k] Binomial[k, 4], {k, 0, n}], {n, 4, 24}]
    Table[Sum[Binomial[n, k] StirlingS2[k, 4] BellB[n - k], {k, 0, n}], {n, 4, 24}]
    Table[(BellB[n] - 24*BellB[n+1] + 29*BellB[n+2] - 10*BellB[n+3] + BellB[n+4])/24, {n, 4, 24}] (* Vaclav Kotesovec, Aug 06 2021 *)
    With[{nn=30},Drop[CoefficientList[Series[(Exp[Exp[x]-1](Exp[x]-1)^4)/4!,{x,0,nn}],x] Range[0,nn]!,4]] (* Harvey P. Dale, Oct 03 2024 *)
  • PARI
    my(x='x+O('x^25)); Vec(serlaplace(exp(exp(x)-1)*(exp(x)-1)^4/4!)) \\ Michel Marcus, Aug 06 2021

Formula

a(n) = Sum_{k=0..n} Stirling2(n,k) * binomial(k,4).
a(n) = Sum_{k=0..n} binomial(n,k) * Stirling2(k,4) * Bell(n-k).
a(n) = (Bell(n) - 24*Bell(n+1) + 29*Bell(n+2) - 10*Bell(n+3) + Bell(n+4))/24. - Vaclav Kotesovec, Aug 06 2021
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