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 1-10 of 11 results. Next

A052748 Expansion of e.g.f.: -(log(1-x))^3.

Original entry on oeis.org

0, 0, 0, 6, 36, 210, 1350, 9744, 78792, 708744, 7036200, 76521456, 905507856, 11589357312, 159580302336, 2352940786944, 36994905688320, 617953469022720, 10929614667747840, 204073497562936320, 4011658382046919680, 82822558521844224000, 1791791417179298304000
Offset: 0

Views

Author

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

Keywords

Comments

Original name: A simple grammar.

Crossrefs

Column k=3 of A225479.

Programs

  • Maple
    spec := [S,{B=Cycle(Z),S=Prod(B,B,B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
    with(combinat):seq(stirling1(j, 3)*3!*(-1)^(j+1), j=0..50); # Leonid Bedratyuk, Aug 07 2012
  • PARI
    a(n) = {3!*stirling(n,3,1)*(-1)^(n+1)} \\ Andrew Howroyd, Jul 27 2020

Formula

E.g.f.: log(1/(1-x))^3.
Recurrence: {a(1)=0, a(0)=0, a(2)=0, a(3)=6, (-1 - 3*n - 3*n^2 - n^3)*a(n+1) + (9*n + 7 + 3*n^2)*a(n+2) + (-6 - 3*n)*a(n+3) + a(n+4)}.
a(n) = stirling1(n, 3)*3!*(-1)^(n+1). - Leonid Bedratyuk, Aug 07 2012
a(n) = 6*A000399(n). - Andrew Howroyd, Jul 27 2020

Extensions

Name changed and terms a(20) and beyond from Andrew Howroyd, Jul 27 2020

A052753 Expansion of e.g.f.: log(1-x)^4.

Original entry on oeis.org

0, 0, 0, 0, 24, 240, 2040, 17640, 162456, 1614816, 17368320, 201828000, 2526193824, 33936357312, 487530074304, 7463742249600, 121367896891776, 2089865973021696, 37999535417459712, 727710096185266176, 14642785817771802624, 308902349883623731200, 6818239581643475251200
Offset: 0

Views

Author

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

Keywords

Comments

Previous name was: A simple grammar.

Crossrefs

Column k=4 of A225479.

Programs

  • Maple
    spec := [S,{B=Cycle(Z),S=Prod(B,B,B,B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
  • Mathematica
    CoefficientList[Series[(Log[1-x])^4, {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Sep 30 2013 *)
  • PARI
    x='x+O('x^30); concat(vector(4), Vec(serlaplace((log(1-x))^4))) \\ G. C. Greubel, Aug 30 2018
    
  • PARI
    a(n) = {4!*stirling(n,4,1)*(-1)^n} \\ Andrew Howroyd, Jul 27 2020

Formula

E.g.f.: log(-1/(-1+x))^4.
Recurrence: {a(1)=0, a(0)=0, a(2)=0, (1+4*n+6*n^2+4*n^3+n^4)*a(n+1) + (-4*n^3-15-18*n^2-28*n)*a(n+2) + (6*n^2+24*n+25)*a(n+3) + (-4*n-10)*a(n+4)+a(n+5), a(3)=0, a(4)=24}.
a(n) ~ (n-1)! * 2*log(n)*(2*log(n)^2 + 6*gamma*log(n) - Pi^2 + 6*gamma^2), where gamma is Euler-Mascheroni constant (A001620). - Vaclav Kotesovec, Sep 30 2013
a(n) = 24*A000454(n) = 4!*(-1)^n*Stirling1(n,4). - Andrew Howroyd, Jul 27 2020

Extensions

New name using e.g.f., Vaclav Kotesovec, Sep 30 2013

A052767 Expansion of e.g.f.: -(log(1-x))^5.

Original entry on oeis.org

0, 0, 0, 0, 0, 120, 1800, 21000, 235200, 2693880, 32319000, 410031600, 5519487600, 78864820320, 1194924450720, 19166592681600, 324817601472000, 5803921108010880, 109115988701293440, 2154085473710580480, 44566174481427360000, 964537418717406213120, 21799797542483649131520
Offset: 0

Views

Author

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

Keywords

Crossrefs

Column k=5 of A225479.

Programs

  • Maple
    spec := [S,{B=Cycle(Z),S=Prod(B,B,B,B,B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
  • Mathematica
    With[{nn=20},CoefficientList[Series[-(Log[1-x])^5,{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Oct 14 2019 *)
  • PARI
    a(n) = {5!*stirling(n,5,1)*(-1)^(n+1)} \\ Andrew Howroyd, Jul 27 2020

Formula

E.g.f.: log(-1/(-1+x))^5.
Recurrence: a(1)=0, a(0)=0, a(2)=0, a(4)=0, a(3)=0, (-1-5*n-10*n^2-10*n^3-5*n^4-n^5)*a(n+1) + (31+5*n^4+70*n^2+30*n^3+75*n)*a(n+2) + (-125*n-90-60*n^2-10*n^3)*a(n+3) + (10*n^2+65+50*n)*a(n+4) + (-15-5*n)*a(n+5) + a(n+6)=0, a(5)=120.
a(n) = 120*A000482(n) = 5!*Stirling1(n,5)*(-1)^(n+1). - Andrew Howroyd, Jul 27 2020

Extensions

Definition clarified by Harvey P. Dale, Oct 14 2019
Terms a(20) and beyond from Andrew Howroyd, Jul 27 2020

A052779 Expansion of e.g.f.: (log(1-x))^6.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 720, 15120, 231840, 3265920, 45556560, 649479600, 9604465200, 148370508000, 2402005525920, 40797624067200, 726963917097600, 13580328282393600, 265689107448756480, 5437099866285377280, 116229410301685651200, 2591985252922277184000, 60218914823672258142720
Offset: 0

Views

Author

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

Keywords

Comments

Original name: a simple grammar.

Crossrefs

Column k=6 of A225479.

Programs

  • Maple
    spec := [S,{B=Cycle(Z),S=Prod(B,B,B,B,B,B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
  • PARI
    a(n) = {6!*stirling(n,6,1)*(-1)^n} \\ Andrew Howroyd, Jul 27 2020

Formula

E.g.f.: log(-1/(-1+x))^6.
Recurrence: {a(1)=0, a(0)=0, a(2)=0, a(4)=0, a(3)=0, a(5)=0, a(6)=720, (1+15*n^2+6*n+6*n^5+15*n^4+20*n^3+n^6)*a(n+1) + (-63-186*n-225*n^2-6*n^5-45*n^4-140*n^3)*a(n+2) + (540*n+120*n^3+375*n^2+15*n^4+301)*a(n+3) + (-390*n-20*n^3-350-150*n^2)*a(n+4) + (140+15*n^2+90*n)*a(n+5) + (-21-6*n)*a(n+6) + a(n+7)}.
a(n) = 720*A001233(n) = 6!*(-1)^n*Stirling1(n,6). - Andrew Howroyd, Jul 27 2020

Extensions

Name changed and terms a(20) and beyond from Andrew Howroyd, Jul 27 2020

A225475 Triangle read by rows, 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, 1, 3, 4, 2, 15, 23, 18, 6, 105, 176, 172, 96, 24, 945, 1689, 1900, 1380, 600, 120, 10395, 19524, 24278, 20880, 12120, 4320, 720, 135135, 264207, 354662, 344274, 241080, 116760, 35280, 5040, 2027025, 4098240, 5848344, 6228096, 4993296, 2956800, 1229760
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,    1,
[2]    3,    4,    2,
[3]   15,   23,   18,    6,
[4]  105,  176,  172,   96,  24,
[5]  945, 1689, 1900, 1380, 600, 120.
		

Crossrefs

Cf. A028338, A225479 (m=1), A048594.

Programs

  • Mathematica
    SFCO[n_, k_, m_] := SFCO[n, k, m] = If[ k > n || k < 0, Return[0], If[ n == 0 && k == 0, Return[1], Return[ k*SFCO[n - 1, k - 1, m] + (m*n - 1)*SFCO[n - 1, k, m]]]]; Table[ SFCO[n, k, 2], {n, 0, 8}, {k, 0, n}] // Flatten  (* Jean-François Alcover, Jul 02 2013, translated from Sage *)
  • Sage
    @CachedFunction
    def SF_CO(n, k, m):
        if k > n or k < 0 : return 0
        if n == 0 and k == 0: return 1
        return k*SF_CO(n-1, k-1, m) + (m*n-1)*SF_CO(n-1, k, m)
    for n in (0..8): [SF_CO(n, k, 2) for k in (0..n)]

Formula

For a recurrence see the Sage program.
T(n, 0) ~ A001147; T(n, 1) ~ A004041.
T(n, n) ~ A000142; T(n, n-1) ~ A001563.
T(n,k) = A028338(n,k)*A000142(k). - Philippe Deléham, Jun 24 2015

A344498 a(n) = |Stirling1(n, floor(n/2))| * floor(n/2)!.

Original entry on oeis.org

1, 0, 1, 2, 22, 100, 1350, 9744, 162456, 1614816, 32319000, 410031600, 9604465200, 148370508000, 3986353491120, 72622987557120, 2202727143576960, 46243059751848960, 1563325251963995520, 37165349757066935040, 1385918755006365216000, 36804377751967949760000
Offset: 0

Views

Author

Peter Luschny, May 22 2021

Keywords

Crossrefs

Cf. A132393, A225479 (middle column), A344397.

Programs

  • Maple
    a := n -> abs(Stirling1(n, floor(n/2))) * floor(n/2)! :
    seq(a(n), n = 0..21);
  • Mathematica
    a[n_] := Abs @ StirlingS1[n, Floor[n/2]] * Floor[n/2]!; Array[a, 22, 0] (* Amiram Eldar, May 22 2021 *)

Formula

a(n) = floor(n/2)! * [x^floor(n/2)] Pochhammer(x, n).

A372347 a(n) = Sum_{j=0..n} p(n - j, j) where p(n, x) = Sum_{k=0..n} k! * Stirling1(n, k) * x^k.

Original entry on oeis.org

1, 1, 2, 4, 12, 52, 334, 2866, 31902, 439510, 7372150, 147351714, 3460114654, 94073798158, 2926942982790, 103161703653178, 4084845678671086, 180433041383154870, 8836346732709839206, 477142911818397135058, 28265453383985064929934
Offset: 0

Views

Author

Peter Luschny, Apr 28 2024

Keywords

Crossrefs

Cf. A225479.

Programs

  • Maple
    p := n -> local k; add(k!*Stirling1(n, k)*x^k, k = 0..n):
    a := n -> local j; add(subs(x=j, p(n - j)), j = 0..n):
    seq(a(n), n = 0..21);

A376873 a(n) = n! * |Stirling1(2*n, n)|.

Original entry on oeis.org

1, 1, 22, 1350, 162456, 32319000, 9604465200, 3986353491120, 2202727143576960, 1563325251963995520, 1385918755006365216000, 1500893038955163069216000, 1949720475921117012670233600, 2992360962617823634351113600000, 5356716752093284789859604692736000
Offset: 0

Views

Author

Peter Luschny, Oct 29 2024

Keywords

Crossrefs

Programs

  • Maple
    a := n -> n! * abs(Stirling1(2*n, n)):
    seq(a(n), n = 0..14);
  • Mathematica
    Array[#!*Abs[StirlingS1[2 #, #]] &, 14] (* Michael De Vlieger, Oct 29 2024 *)
  • PARI
    a(n) = n!*abs(stirling(2*n, n, 1)); \\ Michel Marcus, Oct 29 2024
    
  • Python
    from sympy.functions.combinatorial.numbers import factorial, stirling
    def A376873(n): return factorial(n)*stirling(n<<1,n,kind=1) # Chai Wah Wu, Oct 29 2024

Formula

a(n) = n!*A187646(n).
a(n) = A225479(2*n, 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

A356654 Triangle read by rows. T(n, k) = k! * Sum_{j=k..n} Lah(n, j) * Stirling2(j, k), where Lah(n, k) = A271703(n, k).

Original entry on oeis.org

1, 0, 1, 0, 3, 2, 0, 13, 18, 6, 0, 73, 158, 108, 24, 0, 501, 1510, 1590, 720, 120, 0, 4051, 15962, 23040, 15960, 5400, 720, 0, 37633, 186270, 345786, 325920, 168000, 45360, 5040, 0, 394353, 2385182, 5469492, 6579384, 4594800, 1884960, 423360, 40320
Offset: 0

Views

Author

Peter Luschny, Sep 01 2022

Keywords

Comments

The same construction with Stirling1 in place of Stirling2 gives A225479, the ordered Stirling cycle numbers.

Examples

			Triangle T(n, k) begins:
[0] 1;
[1] 0,      1;
[2] 0,      3,       2;
[3] 0,     13,      18,       6;
[4] 0,     73,     158,     108,      24;
[5] 0,    501,    1510,    1590,     720,     120;
[6] 0,   4051,   15962,   23040,   15960,    5400,     720;
[7] 0,  37633,  186270,  345786,  325920,  168000,   45360,   5040;
[8] 0, 394353, 2385182, 5469492, 6579384, 4594800, 1884960, 423360, 40320;
		

Crossrefs

Cf. A271703, A048993, A225479, A000262 (column 1), A052838 (column 2), A084358 (row sums).

Programs

  • Maple
    L := (n, k) -> `if`(n = k, 1, binomial(n-1, k-1) * n! / k!):
    T := (n, k) -> k! * add(L(n, j) * Stirling2(j, k), j = k..n):
    seq(seq(T(n, k), k = 0..n), n = 0..9);
  • Mathematica
    T[n_, k_] := k! * Sum[Binomial[n, j] * FactorialPower[n - 1, n - j] * StirlingS2[j, k], {j, k, n}]; Table[T[n, k], {n, 0, 8}, {k, 0, n}] // Flatten (* Amiram Eldar, Sep 01 2022 *)
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