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 1-4 of 4 results.

A277001 Denominators of an asymptotic series for the Gamma function (even power series).

Original entry on oeis.org

1, 24, 5760, 2903040, 1393459200, 367873228800, 24103053950976000, 115694658964684800, 9440684171518279680000, 271211974879377138647040000, 3579998068407778230140928000000, 1976158933761093583037792256000000, 258955866680053703121272297226240000000
Offset: 0

Views

Author

Peter Luschny, Sep 25 2016

Keywords

Comments

For formulas and references see A277000 which is the main entry for this rational sequence.

Examples

			The underlying rational sequence starts:
1, 0, -1/24, 0, 19/5760, 0, -2561/2903040, 0, 874831/1393459200, 0, ...
		

Crossrefs

Cf. A277000 (numerators), A277002/A277003 (odd power series).

Programs

  • Maple
    b := n -> CompleteBellB(n,0,seq((k-2)!*bernoulli(k,1/2),k=2..n))/n!:
    A277001 := n -> denom(b(2*n)): seq(A277001(n), n=0..12);
  • Mathematica
    CompleteBellB[n_, zz_] := Sum[BellY[n, k, zz[[1 ;; n-k+1]]], {k, 1, n}];
    b[n_] := CompleteBellB[n, Join[{0}, Table[(k-2)! BernoulliB[k, 1/2], {k, 2, n}]]]/n!;
    a[n_] := Denominator[b[2n]];
    Table[a[n], {n, 0, 12}] (* Jean-François Alcover, Sep 09 2018 *)

A277002 Numerators of an asymptotic series for the Gamma function (odd power series).

Original entry on oeis.org

-1, 7, -31, 127, -511, 1414477, -8191, 118518239, -5749691557, 91546277357, -23273283019, 1982765468311237, -22076500342261, 455371239541065869, -925118910976041358111, 16555640865486520478399, -1302480594081611886641, 904185845619475242495834469891
Offset: 1

Views

Author

Peter Luschny, Sep 26 2016

Keywords

Comments

Let y = x+1/2 then Gamma(x+1) ~ sqrt(2*Pi)*(y/E)^y*exp(Sum_{k>=1} r(k)/y^(2*k-1)) as x -> oo and r(k) = A277002(k)/A277003(k) (see example 7.1 in the Wang reference).
See also theorem 2 and formula (58) in Borwein and Corless. - Peter Luschny, Mar 31 2017

Examples

			The underlying rational sequence b(n) starts:
0, -1/24, 0, 7/2880, 0, -31/40320, 0, 127/215040, 0, -511/608256, ...
		

Crossrefs

Cf. A277003 (denominators), A277000/A277001 (even power series).

Programs

  • Maple
    b := n -> `if`(n=0, 0, bernoulli(n+1, 1/2)/(n*(n+1))):
    a := n -> numer(b(2*n-1)):
    seq(a(n), n=1..18);
  • Mathematica
    b[n_] := BernoulliB[n+1, 1/2]/(n(n+1));
    a[n_] := Numerator[b[2n-1]];
    Array[a, 18] (* Jean-François Alcover, Sep 09 2018 *)

Formula

a(n) = numerator(b(2*n-1)) with b(n) = Bernoulli(n+1, 1/2)/(n*(n+1)) for n>=1, b(0)=0.

A277003 Denominators of an asymptotic series for the Gamma function (odd power series).

Original entry on oeis.org

24, 2880, 40320, 215040, 608256, 738017280, 1277952, 4010803200, 32006209536, 65745715200, 1736441856, 12641296711680, 10066329600, 12611097722880, 1337897345089536, 1086454927196160, 3401614098432, 83088011510887219200, 61022895341568
Offset: 1

Views

Author

Peter Luschny, Sep 26 2016

Keywords

Comments

For formulas and references see A277002 which is the main entry for this rational sequence.

Examples

			The underlying rational sequence b(n) starts:
0, -1/24, 0, 7/2880, 0, -31/40320, 0, 127/215040, 0, -511/608256, ...
		

Crossrefs

Cf. A277002 (numerators), A277000/A277001 (even power series).

Programs

  • Maple
    b := n -> `if`(n=0, 0, bernoulli(n+1, 1/2)/(n*(n+1))):
    a := n -> denom(b(2*n-1)):
    seq(a(n), n=1..19);
  • Mathematica
    b[n_] := BernoulliB[n+1, 1/2]/(n(n+1));
    a[n_] := Denominator[b[2n-1]];
    Array[a, 19] (* Jean-François Alcover, Sep 09 2018 *)

Formula

a(n) = denominator(b(2*n-1)) with b(n) = Bernoulli(n+1, 1/2)/(n*(n+1)) for n>=1, b(0)=0.

A276996 Numerators of coefficients of polynomials arising from applying the complete Bell polynomials to k!B_k(x)/(k*(k-1)) with B_k(x) the Bernoulli polynomials.

Original entry on oeis.org

1, 0, 0, 1, -1, 1, 0, 1, -3, 1, 1, -1, 6, -10, 5, 0, -1, -15, 95, -40, 16, 239, -1, 13, -85, 240, -237, 79, 0, 403, 21, 385, -1575, 3577, -2947, 421, -46409, -239, 3841, 175, 861, -8036, 45458, -10692, 2673, 0, -82451, -2657, 56177, 1638, 19488, -85260, 139656, -86472, 19216
Offset: 0

Views

Author

Peter Luschny, Oct 01 2016

Keywords

Comments

The polynomials appear in certain asymptotic series for the Gamma function, cf. for example A181855/A181856 and A277000/A277001.

Examples

			Polynomials start:
p_0(x) = 1;
p_1(x) = 0;
p_2(x) = 1/6 + -x + x^2;
p_3(x) = (1/2)*x + -(3/2)*x^2 + x^3;
p_4(x) = 1/60 + -x + 6*x^2 + -10*x^3 + 5*x^4;
p_5(x) = -(1/6)*x + -(15/2)*x^2 + (95/3)*x^3 + -40*x^4 + 16*x^5;
p_6(x) = 239/504 + -(1/4)*x + (13/4)*x^2 + -85*x^3 + 240*x^4 + -237*x^5 + 79*x^6;
Triangle starts:
1;
0,   0;
1,  -1,   1;
0,   1,  -3,   1;
1,  -1,   6, -10,  5;
0,  -1, -15,  95, -40,   16;
239,-1,  13, -85, 240, -237, 79;
		

Crossrefs

Cf. A276997 (denominators); T(2n,0) = A181855(n), T(n,n) = A203852(n).
Cf. A276998.

Programs

  • Maple
    A276996_row := proc(n) local p;
    p := (n,x) -> CompleteBellB(n,0,seq((k-2)!*bernoulli(k,x),k=2..n)):
    seq(numer(coeff(p(n,x),x,k)), k=0..n) end:
    seq(A276996_row(n), n=0..9);
    # Recurrence for the polynomials:
    A276996_poly := proc(n,x) option remember; local z;
    if n = 0 then return 1 fi; z := proc(k) option remember;
    if k=1 then 0 else (k-2)!*bernoulli(k,x) fi end;
    expand(add(binomial(n-1,j)*z(n-j)*A276996_poly(j,x),j=0..n-1)) end:
    for n from 0 to 5 do sort(A276996_poly(n,x)) od;
  • Mathematica
    CompleteBellB[n_, zz_] := Sum[BellY[n, k, zz[[1 ;; n-k+1]]], {k, 1, n}];
    p[n_, x_] := CompleteBellB[n, Join[{0}, Table[(k-2)! BernoulliB[k, x], {k, 2, n}]]];
    row[0] = {1}; row[1] = {0, 0}; row[n_] := CoefficientList[p[n, x], x] // Numerator;
    Table[row[n], {n, 0, 9}] // Flatten (* Jean-François Alcover, Sep 09 2018 *)

Formula

T(n,k) = Numerator([x^k] p_n(x)) where p_n(x) = Y_{n}(z_1, z_2, z_3,..., z_n) are the complete Bell polynomials evaluated at z_1 = 0 and z_k = (k-2)!*B_k(x) for k>1 and B_k(x) the Bernoulli polynomials.
Showing 1-4 of 4 results.