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 10 results.

A229979 Numerators of interleaved A063524(n) and A002427(n)/A006955(n).

Original entry on oeis.org

0, 1, 1, 1, 0, -1, 0, 1, 0, -3, 0, 5, 0, -691, 0, 35, 0, -3617, 0, 43867, 0, -1222277, 0, 854513, 0, -1181820455, 0, 76977927, 0, -23749461029, 0, 8615841276005, 0, -84802531453387, 0, 90219075042845, 0
Offset: 0

Views

Author

Paul Curtz, Oct 05 2013

Keywords

Comments

Numerators of Br(n) = 0, 1, 1, 1/2, 0, -1/6, 0, 1/6, 0, -3/10, 0, 5/6, 0, -691/210,... complementary Bernoulli numbers.
A164555(n)/A027642(n) is an autosequence of second kind. Its inverse binomial transform is the signed sequence and its main diagonal is the double of the first upper diagonal.
Br(n) is an autosequence of first kind. Its inverse binomial transform is the signed sequence and its main diagonal is A000004=0's.
Br(n) difference table:
0, 1, 1, 1/2, 0, -1/6,...
1, 0, -1/2, -1/2, -1/6, 1/6,... =A140351(n)/A140219(n)
-1, -1/2, 0, 1/3, 1/3, 0,...
1/2, 1/2, 1/3, 0, -1/3, -1/3,...
0, -1/6, -1/3, -1/3, 0, 8/15,...
-1/6, -1/6, 0, 1/3, 8/15, 0,... etc.

Crossrefs

Cf. A050925: a similar sequence, because 2*(n+1)*B(n) and (n+1)*B(n) have the same numerator.

Programs

  • Mathematica
    a[0] = 0; a[1] = a[2] = 1; a[n_] := 2*n*BernoulliB[n-1] // Numerator; Table[a[n], {n, 0, 36}] (* Jean-François Alcover, Nov 25 2013 *)

Formula

a(2n)=A063524(n). a(2n+1)=A002427(n).
a(n) = numerators of n * b(n) with b(n)=0 followed by A164555(n)/A027642(n) = 0, 1, 1/2, 1/6, 0,... in A165142(n).
a(n+1) = numerators of Br(n+1) = Br(n) + A140351(n)/A140219(n), a(0)=Br(0)=0.

Extensions

Cross-ref. to A050925 by Jean-François Alcover, Dec 09 2013

A232800 Denominators written by antidiagonals of interleaved A063524(n) and A002427(n)/A006955(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 2, 1, 2, 1, 6, 6, 3, 3, 6, 6, 1, 6, 3, 1, 3, 6, 1, 6, 6, 1, 3, 3, 1, 6, 6, 1, 6, 3, 3, 1, 3, 3, 6, 1, 10, 10, 15, 5, 15, 15, 5, 15, 10, 10, 1, 10, 5, 15, 15, 1, 15, 15, 5, 10, 1
Offset: 0

Views

Author

Paul Curtz, Nov 30 2013

Keywords

Comments

The numerators of Br(n)=0, 1, 1, 1/2, 0, -1/6, 0, 1/6, 0, -3/10, 0, 5/6, 0,... are in A229979(n).
(Corresponding complementary Euler numbers Er(n):
A198631(2n+1)/A006519(2n+2)=1/2, -1/4, 1/2, -17/8, 31/2, -691/4,... =Ef2(n). (2*n+2)*Ef2(n)=1, -1, 3, -17, 155, 2073,...=-A001469(n+1),Genocchi numbers. Er(n)=interleaved (A063524(n) and -A001469(n+1)) =0, 1, 1, -1, 0, 3, 0, -17, 0, 155,... =-A226158(n).)

Examples

			1,
1, 1,
1, 1, 1,
2, 2, 2, 2,
1, 2, 1, 2, 1,
6, 6, 3, 3, 6, 6, etc.
Triangle of denominators of Br(n),complementary Bernoulli numbers,written by antidiagonals (see A229979).
		

A006955 Denominator of (2n+1) B_{2n}, where B_n are the Bernoulli numbers.

Original entry on oeis.org

1, 2, 6, 6, 10, 6, 210, 2, 30, 42, 110, 6, 546, 2, 30, 462, 170, 6, 51870, 2, 330, 42, 46, 6, 6630, 22, 30, 798, 290, 6, 930930, 2, 102, 966, 10, 66, 1919190, 2, 30, 42, 76670, 6, 680862, 2, 690, 38874, 470, 6, 46410, 2, 330, 42, 106, 6, 1919190
Offset: 0

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Author

Keywords

Comments

Also denominators of asymptotic expansion of polygamma function psi''(z).

Examples

			(n+1)*B_n gives the sequence 1, -1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66, ...
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 260, (6.4.13).
  • A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 73.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Numerators are in A002427.

Programs

  • Maple
    gf := z / (1 - exp(-z)): ser := series(gf, z, 220):
    seq(denom((n+1)!*coeff(ser, z, n)), n=0..108, 2); # Peter Luschny, Aug 29 2020
  • Mathematica
    Denominator[Table[(2n+1)BernoulliB[2n],{n,0,60}]] (* Harvey P. Dale, Nov 03 2011 *)
  • PARI
    a(n) = denominator((2*n+1)*bernfrac(2*n)); \\ Michel Marcus, Aug 06 2017

Formula

Apparently a(n) = denominator(Sum_{k=0..2*n-1} (-1)^(2*n-k+1)*E1(2*n, k+1)/ binomial(2*n, k+1)), where E1(n, k) denotes the first-order Eulerian numbers A123125. - Peter Luschny, Feb 17 2021

A140351 Numerator of the coefficient [x^1] of the Bernoulli twin number polynomial C(n,x).

Original entry on oeis.org

1, 0, -1, -1, -1, 1, 1, -1, -3, 3, 5, -5, -691, 691, 35, -35, -3617, 3617, 43867, -43867, -1222277, 1222277, 854513, -854513, -1181820455, 1181820455, 76977927, -76977927, -23749461029, 23749461029, 8615841276005, -8615841276005, -84802531453387, 84802531453387
Offset: 1

Views

Author

Paul Curtz, May 30 2008, Jun 23 2008

Keywords

Comments

The Bernoulli twin number polynomials C(n,x) are defined in A129378.

Examples

			The coefficients [x^m]C(n,x) are a table of fractions:
1 ;
-1/2, 1;
-1/3, 0, 1;
-1/6, -1/2, 1/2, 1;
-1/30,-1/2, -1/2, 1, 1;
1/30, -1/6, -1,-1/3, 3/2, 1;
1/42, 1/6, -1/2, -5/3, 0, 2, 1;
-1/42, 1/6, 1/2, -7/6, -5/2, 1/2, 5/2, 1;
-1/30, -1/6, 2/3, 7/6, -7/3, -7/2, 7/6, 3, 1;
1/30, -3/10, -2/3, 2, 7/3, -21/5, -14/3, 2, 7/2, 1;
5/66, 3/10, -3/2, -2, 5, 21/5, -7, -6, 3, 4, 1; ...
This sequence here contains the numerators of the second column.
		

Crossrefs

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:
    A140351 := proc(n) coeff(C(n,x),x,1) ; numer(%) ; end proc: seq(A140351(n),n=1..80) ; # R. J. Mathar, Nov 22 2009
  • Mathematica
    b[n_, x_] := Coefficient[ Series[ t*E^(x*t)/(E^t - 1), {t, 0, n}], t, n]*n!; c[n_, x_] := Sum[ Binomial[n-1, j-1]*b[j, x], {j, 1, n}]; t[n_, m_] := Coefficient[c[n, x], x, m]; Table[t[n, 1] // Numerator, {n, 1, 34} ] (* Jean-François Alcover, Mar 04 2013 *)
    Table[Sum[Binomial[n, k]*(k+1)*BernoulliB[k], {k, 0, n}], {n, 0, 30}] // Numerator (* Vaclav Kotesovec, Oct 05 2016 *)
  • Maxima
    makelist(num(sum((binomial(n,i)*(i+1)*bern(i)),i,0,n)),n,0,20); /* Vladimir Kruchinin, Oct 05 2016 */
    
  • PARI
    a(n) = numerator(sum(i=0, n, binomial(n,i)*(i+1)*bernfrac(i))); \\ Michel Marcus, Oct 05 2016

Formula

a(n) = numerator(Sum_{i=0..n} binomial(n,i)*(i+1)*bernoulli(i)). - Vladimir Kruchinin, Oct 05 2016

Extensions

Edited and extended by R. J. Mathar, Nov 22 2009

A006956 Denominator of (2n+1)(2n+2) B_{2n}, where B_n are the Bernoulli numbers. Also denominators of the asymptotic expansion of the polygamma function psi'''(z).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 15, 1, 5, 21, 5, 1, 21, 1, 1, 231, 5, 1, 1365, 1, 55, 21, 1, 1, 663, 11, 5, 57, 5, 1, 15015, 1, 17, 483, 1, 11, 25935, 1, 5, 21, 935, 1, 7917, 1, 23, 19437, 5, 1, 3315, 1, 55, 21, 1, 1, 191919, 253, 2465, 21, 5, 1, 1734915, 1, 1, 17157, 17, 1
Offset: 3

Views

Author

Keywords

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 260, (6.4.14).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Numerators are in A076549. Cf. A006955/A002427.

Programs

  • Mathematica
    Join[{1, 1}, Table[Denominator[(4 n^2 + 6 n + 2) BernoulliB[2 n]], {n, 1, 70}]] (* Vincenzo Librandi, Aug 02 2013 *)

Extensions

More terms from Ralf Stephan, Oct 19 2002

A076549 Numerator of (2n+1)(2n+2) B_{2n}, where B_n are the Bernoulli numbers. Also numerators of the asymptotic expansion of the polygamma function psi'''(z).

Original entry on oeis.org

2, 3, 2, -1, 4, -3, 10, -691, 280, -10851, 438670, -1222277, 3418052, -1181820455, 1077690978, -23749461029, 137853460416080, -84802531453387, 541314450257070, -26315271553053477373, 761798417598805340
Offset: 0

Views

Author

Ralf Stephan, Oct 19 2002

Keywords

Crossrefs

Denominators are in A006956. Cf. A002427/A006955.

Programs

  • Mathematica
    Join[{2, 3}, Table[Numerator[(4 n^2 + 6 n + 2) BernoulliB[2 n]], {n, 1, 30}]] (* Vincenzo Librandi, Aug 02 2013 *)

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

A290533 Numerator of 2*n*(2*n+1) B_{2*n}, where B_n are the Bernoulli numbers.

Original entry on oeis.org

0, 1, -2, 1, -12, 25, -1382, 245, -28936, 131601, -2444554, 9399643, -4727281820, 1000713051, -332492454406, 43079206380025, -1356840503254192, 1533724275728365, -157891629318320864238, 723708496718865073, -1044330873985796488204
Offset: 0

Views

Author

Seiichi Manyama, Aug 05 2017

Keywords

Comments

In 1997, Matiyasevich found the following identity;
(n+2) * Sum_{k=2..n-2} B_k*B_{n-k} - 2 * Sum_{k=2..n-2} binomial(n+2, k)*B_k*B_{n-k} = n*(n+1)*B_n for n > 3.

Examples

			B_n gives the sequence 1, -1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66, 0, -691/2730, ...
n*(n+1)*B_n gives the sequence 0, -1, 1, 0, -2/3, 0, 1, 0, -12/5, 0, 25/3, 0, -1382/35, 0, 245, 0, -28936/15, ...
		

Crossrefs

A290534 Denominator of 2*n*(2*n+1) B_{2*n}, where B_n are the Bernoulli numbers.

Original entry on oeis.org

1, 1, 3, 1, 5, 3, 35, 1, 15, 7, 11, 3, 91, 1, 15, 77, 85, 3, 8645, 1, 33, 1, 23, 3, 1105, 11, 15, 133, 145, 3, 31031, 1, 51, 161, 5, 33, 319865, 1, 15, 7, 7667, 3, 16211, 1, 345, 6479, 235, 3, 7735, 1, 33, 7, 53, 3, 319865, 23, 7395, 7, 295, 3, 7055321, 1, 3, 817
Offset: 0

Views

Author

Seiichi Manyama, Aug 05 2017

Keywords

Comments

In 1997, Matiyasevich found the following identity;
(n+2) * Sum_{k=2..n-2} B_k*B_{n-k} - 2 * Sum_{k=2..n-2} binomial(n+2, k)*B_k*B_{n-k} = n*(n+1)*B_n for n > 3.

Crossrefs

A242246 Numerators of n*A164555(n-1)/A027642(n-1).

Original entry on oeis.org

0, 1, 1, 1, 0, -1, 0, 1, 0, -3, 0, 5, 0, -691, 0, 35, 0, -3617, 0, 43867, 0, -1222277, 0, 854513, 0, -1181820455, 0, 76977927, 0, -23749461029, 0, 8615641276005, 0, -84802531453387, 0, 90219075042845, 0
Offset: 0

Views

Author

Paul Curtz, May 09 2014

Keywords

Comments

First multiplied shifted (second) Bernoulli numbers.
A164555(n-1)/A027642(n-1) = 0 followed by (A164555(n)/A027642(n)=1, 1/2, 1/6,...) = f(n) = 0, 1, 1/2, 1/6, 0,... .
f(n+1) - f(n) = A051716(n)/A051717(n).
Generally we consider a transform applied to the autosequences of first or second kind. An autosequence is a sequence which has its inverse binomial transform equal to the signed sequence. It is of the first kind if the main diagonal is A000004=0's. It is of the second kind if the main diagonal is the first upper diagonal multiplied by 2. A000045(n) is an autosequence of the first kind. A164555(n)/A027642(n) is an autosequence of the second kind. See A190339 (and A241269).
Here we apply the transform to the Bernoulli numbers A164555(n)/A027642(n).
We take n*(0 followed by A164555(n)/A027642(n)).
Hence the autosequence of first kind
TB1(n) = 0, 1, 1, 1/2, 0, -1/6, 0, 1/6, 0, -3/10, 0, 5/6, O, -691/210,.. .
a(n) are the numerators.
The first seven rows of the differencece table of TB1(n) are
0, 1, 1, 1/2, 0, - 1/6, 0, 1/6,...
1, 0, -1/2, -1/2, -1/6, 1/6, 1/6, -1/6,... =A140351(n+1)/b(n+1)
-1, -1/2, 0, 1/3, 1/3, 0, -1/3, -2/15,...
1/2, 1/2, 1/3, 0, -1/3, -1/3, 1/5, 11/15,...
0, -1/6, -1/3, -1/3, 0, 8/15, 8/15, -4/5,...
-1/6, -1/6, 0, 1/3, 8/15, 0, -4/3, -4/3,...
0, 1/6, 1/3, 1/5, -8/15, -4/3, 0, 512/105,... .
First and second upper diagonals: 1, -1/2, 1/3, -1/3, 8/15, -4/3, 512/105,... .
Sum of the antidiagonals:
0, 1, 1, 0, -1/2, 0, 1/2, 0, -5/6, 0, 13/6, 0, -49/6, 0,... .
(Note that the same transform applied to the second fractional Euler numbers A198631(n)/A006519(n+1) yields the Genocchi numbers -A226158(n)).
This transform can be continued:
TB2(n) = n*(0 followed by TB1(n)) =
0, 0, 2, 3, 2, 0, -1, 0, 4/3, 0, -3, 0, 10, 0, -691/15, 0, 280, 0,...
is an autosequence of second kind.
TB3(n) = 0, 0, 0, 6, 12, 10, 0, -7, 0, 12, 0, -33, 0, 130, 0, 691, 0,...
is apparently an integer autosequence of the first kind.

Crossrefs

Cf. A199969 (autosequence).

Formula

a(n) = 0 followed by (A050925(n) = 1, -1, 1, 0,... ) with 1 instead of -1.
a(2n) = A063524(n). a(2n+1) = A002427(n).
Showing 1-10 of 10 results.