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.

Previous Showing 11-20 of 25 results. Next

A141412 Triangle c(n,k) of the denominators of coefficients [x^k] P(n,x) of the polynomials P(n,x) of A129891.

Original entry on oeis.org

1, 2, 1, 3, 1, 1, 4, 12, 2, 1, 5, 6, 4, 1, 1, 6, 180, 8, 6, 2, 1, 7, 10, 15, 2, 6, 1, 1, 8, 560, 240, 240, 6, 4, 2, 1, 9, 1260, 15120, 20, 144, 1, 12, 1, 1, 10, 12600, 672, 945, 32, 240, 8, 3, 2, 1, 11, 1260, 8400, 1512, 3024, 48, 240, 3, 1, 1, 1, 12, 166320, 100800, 64800, 12096, 12096, 480, 360, 4, 12, 2, 1
Offset: 0

Views

Author

Paul Curtz, Aug 04 2008

Keywords

Comments

Polynomials are characteristic polynomials of a particular John Couch Adams matrix.
General term: ( (-1)^(n-j)*C(j, n)*n! ) * Integral_{0..i} (u*(u-1)*(u-2)* ... *(u-n))/(u-j)) du, with 1 <= i,j <= n (see Flajolet et al.).
Denominators are 1, 2, 12, 24, 720 = A091137.
These polynomials come from the explicit case. The less interesting implicit case has the same denominators (see P. Curtz reference).

Examples

			Triangle begins:
  1;
  2,   1;
  3,   1,  1;
  4,  12,  2,  1;
  5,   6,  4,  1,  1;
  6, 180,  8,  6,  2,  1;
  7,  10, 15,  2,  6,  1,  1;
  ...
		

References

  • Paul Curtz, Intégration .. note 12, C.C.S.A., Arcueil 1969, p. 61; ibid. pp. 62-65.
  • P. Flajolet, X. Gourdon, and B. Salvy, Sur une famille de polynômes issus de l'analyse numérique, Gazette des Mathématiciens, 1993, 55, pp. 67-78.

Crossrefs

Cf. A000254, A048594, A129891, A140749 (numerators).

Programs

  • Magma
    [Denominator(Factorial(k)*StirlingFirst(n, k)/Factorial(n)): k in [1..n], n in [1..12]]; // G. C. Greubel, Oct 24 2023
    
  • Maple
    P := proc(n,x) option remember ; if n =0 then 1; else (-1)^n/(n+1)+x*add( (-1)^i/(i+1)*procname(n-1-i,x),i=0..n-1) ; expand(%) ; fi; end:
    A141412 := proc(n,k) p := P(n,x) ; denom(coeftayl(p,x=0,k)) ; end: seq(seq(A141412(n,k),k=0..n),n=0..13) ; # R. J. Mathar, Aug 24 2009
  • Mathematica
    p[0]=1; p[n_]:= p[n]= (-1)^n/(n+1) +x*Sum[(-1)^k*p[n-1-k]/(k+1), {k, 0, n-1}];
    Denominator[Flatten[Table[CoefficientList[p[n], x], {n,0,11}]]][[1 ;; 72]] (* Jean-François Alcover, Jun 17 2011 *)
    Table[Denominator[(k+1)!*StirlingS1[n+1,k+1]/(n+1)!], {n,0,12}, {k,0, n}]//Flatten (* G. C. Greubel, Oct 24 2023 *)
  • SageMath
    def A141412(n,k): return denominator(factorial(k+1)* stirling_number1(n+1,k+1)/factorial(n+1))
    flatten([[A141412(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Oct 24 2023

Formula

Conjecture: T(n, k) = d(n+1, k+1), with d(n,k) = denominator(A000254(n, k)*k!/n!) where A000254 are the unsigned Stirling numbers of the 1st kind. See d(n,k) in Farhi link. - Michel Marcus, Oct 18 2018
Equals denominators of A048594(n+1, k+1)/(n+1)!. - G. C. Greubel, Oct 24 2023

Extensions

Partially edited by R. J. Mathar, Aug 24 2009

A140749 Triangle c(n,k) of the numerators of coefficients [x^k] P(n,x) of the polynomials P(n,x) of A129891.

Original entry on oeis.org

1, -1, 1, 1, -1, 1, -1, 11, -3, 1, 1, -5, 7, -2, 1, -1, 137, -15, 17, -5, 1, 1, -7, 29, -7, 25, -3, 1, -1, 363, -469, 967, -35, 23, -7, 1, 1, -761, 29531, -89, 1069, -9, 91, -4, 1, -1, 7129, -1303, 4523, -285, 3013, -105, 29, -9, 1, 1, -671, 16103, -7645, 31063, -781, 4781, -55, 12, -5, 1
Offset: 0

Views

Author

Paul Curtz, Jul 13 2008

Keywords

Comments

The polynomials P(n,x) are defined in A129891: P(0,x)=1 and
P(n,x) = (-1)^n/(n+1) + x* Sum_{i=0..n-1} (-1)^i*P(n-1-i,x)/(i+1) = Sum_{k=0..n} c(n,k)*x^k.

Examples

			The polynomials, for n =0,1,2, ..., are
  P(0, x) = 1;
  P(1, x) = -1/2 + x;
  P(2, x) = 1/3 - x + x^2;
  P(3, x) = -1/4 + 11/12*x - 3/2*x^2 + x^3;
  P(4, x) = 1/5 - 5/6*x + 7/4*x^2 - 2*x^3 + x^4;
  P(5, x) = -1/6 + 137/180*x - 15/8*x^2 + 17/6*x^3 - 5/2*x^4 + x^5;
and the coefficients are
   1;
  -1/2,   1;
   1/3,  -1,       1;
  -1/4,  11/12,   -3/2,   1;
   1/5,  -5/6,     7/4,  -2,     1;
  -1/6, 137/180, -15/8,  17/6,  -5/2,  1;
   1/7,  -7/10,   29/15, -7/2,  25/6, -3,   1;.
		

References

  • Paul Curtz, Gazette des Mathématiciens, 1992, 52, p. 44.
  • Paul Curtz, Intégration Numérique .. Note 12 du Centre de Calcul Scientifique de l'Armement, Arcueil, 1969. Now in 35170, Bruz.
  • P. Flajolet, X. Gourdon, and B. Salvy, Sur une famille de polynômes issus de l'analyse numérique, Gazette des Mathématiciens, 1993, 55, pp. 67-78.

Crossrefs

Cf. A048594, A129891, A141412 (denominators).

Programs

  • Magma
    [Numerator(Factorial(k+1)*StirlingFirst(n+1,k+1)/Factorial(n+1) ): k in [0..n], n in [0..12]]; // G. C. Greubel, Oct 24 2023
    
  • Maple
    P := proc(n,x) option remember ; if n =0 then 1; else (-1)^n/(n+1)+x*add( (-1)^i/(i+1)*procname(n-1-i,x),i=0..n-1) ; expand(%) ; fi; end:
    A140749 := proc(n,k) p := P(n,x) ; numer(coeftayl(p,x=0,k)) ; end: seq(seq(A140749(n, k),k=0..n),n=0..13) ; # R. J. Mathar, Aug 24 2009
  • Mathematica
    p[0] = 1; p[n_] := p[n] = (-1)^n/(n+1) + x*Sum[(-1)^k*p[n-1-k] / (k+1), {k, 0, n-1}];
    Numerator[ Flatten[ Table[ CoefficientList[p[n], x], {n, 0, 11}]]][[1 ;; 69]] (* Jean-François Alcover, Jun 17 2011 *)
    Table[Numerator[(k+1)!*StirlingS1[n+1,k+1]/(n+1)!], {n,0,12}, {k,0,n} ]//Flatten (* G. C. Greubel, Oct 24 2023 *)
  • SageMath
    def A048594(n,k): return (-1)^(n-k)*numerator(factorial(k+1)* stirling_number1(n+1,k+1)/factorial(n+1))
    flatten([[A048594(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Oct 24 2023

Formula

(n+1)*c(n,k) = (n+1-k)*c(n-1,k) - n*c(n-1, k-1). [Edgard Bavencoffe in 1992]
Equals Numerators of A048594(n+1,k+1)/(n+1)!. - Paul Curtz, Jul 17 2008

Extensions

Edited and extended by R. J. Mathar, Aug 24 2009

A320079 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f. 1/(1 + k*log(1 - x)).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 3, 0, 1, 3, 10, 14, 0, 1, 4, 21, 76, 88, 0, 1, 5, 36, 222, 772, 694, 0, 1, 6, 55, 488, 3132, 9808, 6578, 0, 1, 7, 78, 910, 8824, 55242, 149552, 72792, 0, 1, 8, 105, 1524, 20080, 199456, 1169262, 2660544, 920904, 0, 1, 9, 136, 2366, 39708, 553870, 5410208, 28873800, 54093696, 13109088, 0
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 05 2018

Keywords

Examples

			E.g.f. of column k: A_k(x) = 1 + k*x/1! + k*(2*k + 1)*x^2/2! + 2*k*(3*k^2 + 3*k + 1)*x^3/3! + 2*k*(12*k^3 + 18*k^2 + 11*k + 3)*x^4/4! + ...
Square array begins:
  1,    1,     1,      1,       1,       1,  ...
  0,    1,     2,      3,       4,       5,  ...
  0,    3,    10,     21,      36,      55,  ...
  0,   14,    76,    222,     488,     910,  ...
  0,   88,   772,   3132,    8824,   20080,  ...
  0,  694,  9808,  55242,  199456,  553870,  ...
		

Crossrefs

Columns k=0..5 give A000007, A007840, A088500, A354263, A354264, A365588.
Main diagonal gives A317171.

Programs

  • Mathematica
    Table[Function[k, n! SeriesCoefficient[1/(1 + k Log[1 - x]), {x, 0, n}]][j - n], {j, 0, 10}, {n, 0, j}] // Flatten

Formula

E.g.f. of column k: 1/(1 + k*log(1 - x)).
A(n,k) = Sum_{j=0..n} |Stirling1(n,j)|*j!*k^j.
A(0,k) = 1; A(n,k) = k * Sum_{j=1..n} (j-1)! * binomial(n,j) * A(n-j,k). - Seiichi Manyama, May 22 2022

A238685 a(n) = n! * A129505(n) * (-1)^(n+1).

Original entry on oeis.org

1, -6, 210, -17640, 2693880, -649479600, 226750764240, -108116216208000, 67478689070432640, -53382381970299782400, 52192613508738839136000, -61794396463636399635072000, 87121906773549083421777792000, -144222462676882552982237906688000
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 02 2014

Keywords

Crossrefs

Programs

  • Haskell
    a238685 n = a000142 n * a008275 (2 * n - 1) n
    
  • Mathematica
    Array[#!*StirlingS1[2 # - 1, #] &, 14] (* Michael De Vlieger, Jan 24 2022 *)
  • PARI
    a(n) = n!*stirling(2*n-1,n, 1); \\ Michel Marcus, Jan 24 2022
    
  • Python
    from math import factorial
    from sympy.functions.combinatorial.numbers import stirling
    def A238685(n): return factorial(n)*stirling((n<<1)-1,n,kind=1,signed=True) # Chai Wah Wu, Jun 09 2025

Formula

a(n) = A000142(n) * A008275(2*n-1,n).
a(n) = A048594(2*n-1,n).

A075183 One half of third column of triangle A075181.

Original entry on oeis.org

1, 11, 105, 1020, 10500, 115920, 1375920, 17539200, 239500800, 3492720000, 54226972800, 893577484800, 15583119552000, 286816578048000, 5557616064000000, 113108602134528000, 2412627824775168000
Offset: 0

Views

Author

Wolfdieter Lang, Sep 19 2002

Keywords

Comments

Also one half of third diagonal of triangle A048594.

Crossrefs

Formula

a(n) = A075181(n+3, 2)/2 = A048594(n+3, n+1)/2, n>=0.
a(n) = (n+1)!*S1(n+3, n+1)/2 with S1(n, m) := A008275(n, m) (Stirling1).

A140219 Denominator of the coefficient [x^1] of the Bernoulli twin number polynomial C(n,x).

Original entry on oeis.org

1, 1, 2, 2, 6, 6, 6, 6, 10, 10, 6, 6, 210, 210, 2, 2, 30, 30, 42, 42, 110, 110, 6, 6, 546, 546, 2, 2, 30, 30, 462, 462, 170, 170, 6, 6, 51870, 51870, 2, 2, 330, 330, 42, 42, 46, 46, 6, 6, 6630, 6630, 22, 22, 30, 30, 798, 798, 290
Offset: 0

Views

Author

Paul Curtz, Jun 23 2008

Keywords

Comments

See A140351 for the main part of the documentation.

Crossrefs

Cf. A002427, A006955, A048594, A140351 (numerators).

Programs

  • Maple
    C := proc(n, x) if n = 0 then 1; else add(binomial(n-1, j-1)* bernoulli(j, x), j=1..n) ; expand(%) ; end if ; end proc:
    A140219 := proc(n) coeff(C(n, x), x, 1) ; denom(%) ; end proc:
    seq(A140219(n), n=1..80) ; # R. J. Mathar, Sep 22 2011
  • Mathematica
    Table[Sum[Binomial[n, k]*(k+1)*BernoulliB[k], {k, 0, n}], {n, 0, 60}] // Denominator (* Vaclav Kotesovec, Oct 05 2016 *)
  • Maxima
    makelist(denom(sum((binomial(n, i)*(i+1)*bern(i)), i, 0, n)), n, 0, 20); /* Vladimir Kruchinin, Oct 05 2016 */
    
  • PARI
    a(n) = denominator(sum(i=0, n, binomial(n,i)*(i+1)*bernfrac(i))); \\ Michel Marcus, Oct 05 2016

Formula

a(n) = denominator(Sum_{i=0..n} binomial(n,i)*(i+1)*bern(i)). - Vladimir Kruchinin, Oct 05 2016
a(n) = A006955(floor(n/2)). - Georg Fischer, Nov 29 2022

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

A322470 Expansion of e.g.f. 1/(1 + log(1 + x)/(1 + log(1 + x)^2/(1 + log(1 + x)^3/(1 + ...)))), a continued fraction.

Original entry on oeis.org

1, -1, 3, -8, 4, 236, -3892, 54552, -739440, 9704088, -116868648, 1033709040, 4025264736, -592337009328, 23033374965456, -708140910086400, 19418661884145024, -485092601562305664, 10704418782304457088, -180835985547961196544, 431827528992523301376, 162896031123325288266240
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 19 2018

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 21; CoefficientList[Series[1/(1 + ContinuedFractionK[Log[1 + x]^k, 1, {k, 1, nmax}]), {x, 0, nmax}], x] Range[0, nmax]!

Formula

a(n) = Sum_{k=0..n} Stirling1(n,k)*A007325(k)*k!.

A075184 One half of fourth column of triangle A075181.

Original entry on oeis.org

3, 50, 675, 8820, 117600, 1632960, 23814000, 365904000, 5927644800, 101189088000, 1818030614400, 34326452160000, 679990671360000, 14108934647808000, 306113492805120000, 6933770723303424000
Offset: 0

Views

Author

Wolfdieter Lang, Sep 19 2002

Keywords

Comments

Also one half of fourth diagonal of unsigned triangle A048594.

Crossrefs

Formula

a(n) = A075181(n+4, 3)/2 = |A048594(n+4, n+1)|/2, n>=0.
a(n) = -(n+1)!*S1(n+4, n+1)/2 with S1(n, m) := A008275(n, m) (Stirling1).

A075185 One-fourth of fifth column of triangle A075181.

Original entry on oeis.org

6, 137, 2436, 40614, 673470, 11389140, 198793980, 3602823840, 67991283360, 1337641905600, 27440275262400, 586731694348800, 13067437397414400, 302870068070169600, 7298072456298624000
Offset: 0

Views

Author

Wolfdieter Lang, Sep 19 2002

Keywords

Comments

Also one-fourth of fifth diagonal of triangle A048594.

Crossrefs

Formula

a(n) = A075181(n+5, 4)/4 = A048594(n+5, n+1)/4, n>=0.
a(n) = (n+1)!*S1(n+5, n+1)/4 with S1(n, m) := A008275(n, m) (Stirling1).
Previous Showing 11-20 of 25 results. Next