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 1-3 of 3 results.

A001898 Denominators of Bernoulli polynomials B(n)(x).

Original entry on oeis.org

1, 2, 12, 8, 240, 96, 4032, 1152, 34560, 7680, 101376, 18432, 50319360, 7741440, 6635520, 884736, 451215360, 53084160, 42361159680, 4459069440, 1471492915200, 140142182400, 1758147379200, 152882380800, 417368899584000, 33389511966720, 15410543984640
Offset: 0

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Keywords

Examples

			The Bernoulli polynomials B(0)(x) through B(6)(x) are:
1;
-(1/2)*x;
(1/12)*(3*x-1)*x;
-(1/8)*(x-1)*x^2;
(1/240)*(15*x^3-30*x^2+5*x+2)*x;
-(1/96)*(x-1)*(3*x^2-7*x-2)*x^2;
(1/4032)*(63*x^5-315*x^4+315*x^3+91*x^2-42*x-16)*x.
		

References

  • F. N. David, Probability Theory for Statistical Methods, Cambridge, 1949; see pp. 103-104. [There is an error in the recurrence for B_s^{(r)}.]
  • N. E. Nørlund, Vorlesungen über Differenzenrechnung. Springer-Verlag, Berlin, 1924, p. 459.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    B:=bernoulli; b:=proc(s) option remember; local t; global r; if s=0 then RETURN(1); fi; expand((-r/s)*add( (-1)^t*binomial(s,t)*B(t)*b(s-t),t=1..s)); end; [seq(denom(b(n)),n=0..30)];
  • Mathematica
    B[s_] := B[s] = If[s == 0, 1, (-x/s)*Sum[(-1)^t*Binomial[s, t]*
       BernoulliB[t]*B[s - t], {t, 1, s}]] // Factor;
    a[n_] := If[n == 0, 1, B[n] // First // Denominator];
    Table[a[n], {n, 0, 26}] (* Jean-François Alcover, Jul 24 2022 *)

Formula

These Bernoulli polynomials B(s) = B(s)(x) are defined by: B(0) = 1; B(s) = (-x/s)*Sum_{t=1..s} (-1)^t*binomial(s, t)*Bernoulli(t)*B(s-t), where Bernoulli(t) are the usual Bernoulli numbers A027641/A027642. Also B(s)(1) = Bernoulli(s).

Extensions

Entry revised Dec 03 2004

A290030 Leading coefficients of numerators of Norlund's B_{nu}^(n) polynomials (Nørlund, Tafel 5, p. 459).

Original entry on oeis.org

1, -1, 3, -1, 15, -3, 63, -9, 135, -15, 99, -9, 12285, -945, 405, -27, 6885, -405, 161595, -8505, 1403325, -66825, 419175, -18225, 24877125, -995085, 229635, -8505, 528525, -18225, 26101845, -841995, 214708725, -6506325, 1148175, -32805, 31479513975, -850797675
Offset: 0

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Author

Gregory Gerard Wojnar, Jul 17 2017

Keywords

Comments

Let phi_(D,rho) be the average value of a generic degree D monic polynomial f when evaluated at the roots of the rho-th derivative of f, expressed as a polynomial in the averaged symmetric polynomials in the roots of f. [See arXiv:1706.08381 [math,GM], 2017.] The "last" term of phi_(D,rho) is a multiple of the product of all roots of f; the coefficient is expressible as a polynomial h_D(N) in N:=D-rho. These polynomials are of the form h_D(N)= ((-1)^D/(D-1)!)*(D-N)*N^chi(D)*g_D(N) where chi(D) := (1 if D is odd, 0 if D is even) and g_D(N) is a monic polynomial of degree (D-2-chi). The coefficients of the g_D(N) are polynomials in D of the form k_n(D)=(1/Q(n))*(D+t(n))^delta(n)*D^chi(n+1)*u_n(D) where Q(n)=A053657(n), t(n):=2 ceiling(n/2)+1, delta(n):= (1 if n is odd, 2 if n is even). The leading coefficients of u_n(D) are a(n).

Crossrefs

Programs

  • Mathematica
    a[n_] := NorlundB[n, x] // Together // Numerator // Coefficient[#, x, n]&;
    Table[a[n], {n, 0, 37}] (* Jean-François Alcover, Jun 30 2019 *)
  • Sage
    [A100655_row(n)[n] for n in (0..37)] # Peter Luschny, Jul 01 2019

A341109 a(n) = denominator(p(n, x)) / (n!*denominator(bernoulli(n, x))), where p(n, x) = Sum_{k=0..n} E2(n, k)*binomial(x + k, 2*n) / Product_{j=1..n} (j - x) and E2(n, k) are the second-order Eulerian numbers A201637.

Original entry on oeis.org

1, 1, 2, 4, 8, 16, 96, 192, 1152, 768, 1536, 3072, 18432, 36864, 221184, 147456, 884736, 1769472, 10616832, 21233664, 637009920, 424673280, 2548039680, 5096079360, 152882380800, 61152952320, 366917713920, 81537269760, 163074539520, 326149079040, 1956894474240
Offset: 0

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Author

Peter Luschny, Feb 06 2021

Keywords

Comments

The challenge is to characterize the sequence purely arithmetically, i.e., without reference to the Eulerian numbers or the Bernoulli polynomials.

Crossrefs

Programs

  • Maple
    Epoly := proc(n, x) add(combinat:-eulerian2(n, k)*binomial(x+k, 2*n), k = 0..n) / mul(j-x, j = 1..n): simplify(expand(%)) end:
    seq(denom(Epoly(n, x)) / (n!*denom(bernoulli(n, x))), n = 0..30);
  • Mathematica
    A053657[n_] := Product[p^Sum[Floor[(n-1)/((p-1) p^k)], {k,0,n}],{p, Prime[Range[n]]}];
    A144845[n_] := Denominator[Together[BernoulliB[n, x]]];
    A163176[n_] := A053657[n] / n!;
    Table[(n + 1) A163176[n + 1] / A144845[n], {n, 0, 30}]
  • Sage
    def A341109(n): # uses[A341108, A318256]
        return A341108(n)//A318256(n)
    print([A341109(n) for n in (0..30)])

Formula

a(n) = A053657(n+1)/(n!*A144845(n)).
a(n) = (n+1)*A163176(n+1)/A144845(n).
a(n) = A341108(n)/A318256(n).
a(n) = A341107(n)*A324369(n+1).
a(n) = A341108(n)/A324370(n+1).
a(n) = A341108(n)*A007947(n+1)/A144845(n).
a(n) = A341108(n)*A324369(n+1)/A195441(n).
prime(n) divides a(k) for k >= A036689(n).
2^(n-1) divides exactly a(n) for n >= 2.
Showing 1-3 of 3 results.