A120082 -id:A120082 - cp's OEIS frontend

A141590 a(n) = numerator of Bernoulli(2n)/(2n + 1)!. Bisection of A120082.

1, 1, -1, 1, -1, 1, -691, 1, -3617, 43867, -174611, 77683, -236364091, 657931, -3392780147, 1723168255201, -7709321041217, 151628697551, -26315271553053477373, 154210205991661, -261082718496449122051, 1520097643918070802691, -2530297234481911294093

Offset: 0

Paul Curtz, Aug 20 2008

Numerators of the Taylor expansion coefficients of the Debye function D(1,x) at the even powers of x.

			Note that a(34) = -125235502160125163977598011460214000388469 but A255505(34) = -4633713579924631067171126424027918014373353.

Peter Luschny, Table of n, a(n) for n = 0..300
Kevin Acres and David Broadhurst, Eta quotients and Rademacher sums, arXiv:1810.07478 [math.NT], 2018.

Cf. A000367, A001067, A046968, A120082, A255505.

A141590:= func< n | Numerator(BernoulliNumber(2*n)/Factorial(2*n+1)) >;
[A141590(n): n in [0..35]]; // G. C. Greubel, Sep 16 2024

A141590 := proc(n) A120082(2*n) end:
seq(A141590(n), n=0..30) ; # R. J. Mathar, Sep 03 2009
seq(numer(bernoulli(2*n)/(2*n+1)!), n=0..34); # Peter Luschny, Dec 03 2022

Table[Numerator[BernoulliB[2*n]/(2*n+1)!], {n,0,35}] (* G. C. Greubel, Sep 16 2024 *)

def A141590(n): return numerator(bernoulli(2*n)/factorial(2*n+1))
[A141590(n) for n in range(36)] # G. C. Greubel, Sep 16 2024

a(n) = A120082(2*n).

Edited and extended by R. J. Mathar, Sep 03 2009

Edited by Peter Luschny, Dec 03 2022

A141588 Numerators of expansion for Debye function (D(1,x)) A120082 with 1's instead of 0's.

Original entry on oeis.org

1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -691, 1, 1, 1, -3617, 1, 43867, 1, -174611, 1, 77683, 1, -236364091, 1, 657931, 1, -3392780147, 1, 1723168255201, 1, -7709321041217, 1, 151628697551, 1, -26315271553053477373

Offset: 0

Paul Curtz, Aug 20 2008

(Bernoulli numbers numerators) A027641(n)/a(n) is an integer sequence.

Note 1's in denominators A120083. A120082 and A027641 are analogous.

swfact[n_] := n!/Floor[n/2]!^2; a[n_] := 2*Zeta[n]*swfact[n]/(2*Pi)^n*If[Mod[n, 4] == 0, -1, 1]; a[0]=1; a[1]=-1; a[?OddQ] = 0; Numerator[ Table[a[n], {n, 0, 36}]] /. (0 -> 1) (* _Jean-François Alcover, Aug 09 2012 *)

Typo a(14)=7 instead of 1 fixed by Jean-François Alcover, Aug 09 2012

A060054 Numerators of numbers appearing in the Euler-Maclaurin summation formula.

Original entry on oeis.org

-1, 1, 0, -1, 0, 1, 0, -1, 0, 1, 0, -691, 0, 1, 0, -3617, 0, 43867, 0, -174611, 0, 77683, 0, -236364091, 0, 657931, 0, -3392780147, 0, 1723168255201, 0, -7709321041217, 0, 151628697551, 0, -26315271553053477373

Offset: 1

Wolfdieter Lang, Feb 16 2001

a(n+1) = numerator(-Zeta(-n)), n>=1, with Riemann's zeta function. a(1)=-1=-numerator(-Zeta(-0)). For denominators see A075180.
Comment from N. J. A. Sloane, Oct 15 2008: (Start)
It appears that essentially the same sequence of rational numbers arises when we expand 1/(exp(1/x)-1) for large x. Here is the result of applying Bruno Salvy's gdev Maple program (answering a question raised by Roger L. Bagula):
gdev(1/(exp(1/x)-1), x=infinity, 20);
x - 1/2 + (1/12)/x - (1/720)/x^3 + (1/30240)/x^5 - (1/1209600)/x^7 + (1/47900160)/x^9 - (691/1307674368000)/x^11 + (1/74724249600)/x^13 - (3617/10670622842880000)/x^15 + (43867/5109094217170944000)/x^17 - (174611/802857662698291200000)/x^19 + ... (End)

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 16 (3.6.28), p. 806 (23.1.30), p. 886 (25.4.7).

Vincenzo Librandi, Table of n, a(n) for n = 1..600
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 16 (3.6.28), p. 806 (23.1.30), p. 886 (25.4.7).
Zhanna Kuznetsova and Francesco Toppan, Classification of minimal Z_2 X Z_2-graded Lie (super)algebras and some applications, arXiv:2103.04385 [math-ph], 2021.

Denominators of nonzero numbers give A060055.
Cf. A001067 (numerator of B(2*k)/(2*k)).
Cf. A075180.
Cf. also A120082/A227830.
Cf. A242179, A106831, A000142.

a060054 n = a060054_list !! n
a060054_list = -1 : map (numerator . sum) (tail $ zipWith (zipWith (%))
   (zipWith (map . (*)) a000142_list a242179_tabf) a106831_tabf)
-- Reinhard Zumkeller, Jul 04 2014

a[m_] := Sum[(-2)^(-k-1) k! StirlingS2[m,k],{k,0,m}]/(2^(m+1)-1); Table[Numerator[a[i]], {i,0,30}] (* Peter Luschny, Apr 29 2009 *)

a(n):=num((-1)^n*sum(binomial(n+k-1,n-1)*sum((j!*(-1)^(j)*binomial(k,j)*stirling1(n+j,j))/(n+j)!,j,1,k),k,1,n)); /* Vladimir Kruchinin, Feb 03 2013 */

a(n) = numerator(b(n)) with b(1) = -1/2; b(2*k+1) = 0, k >= 1; b(2*k) = B(2*k)/(2*k)! (B(2*n) = B_{2n} Bernoulli numbers: numerators A000367, denominators A002445)

A120083 Denominators of expansion for Debye function for n=1: D(1,x).

Original entry on oeis.org

1, 4, 36, 1, 3600, 1, 211680, 1, 10886400, 1, 526901760, 1, 16999766784000, 1, 1120863744000, 1, 181400588328960000, 1, 97072790126247936000, 1, 16860010916664115200000, 1, 324325300906011525120000, 1

Offset: 0

Wolfdieter Lang, Jul 20 2006

Numerators are found under A120082.

G. C. Greubel, Table of n, a(n) for n = 0..447

Cf. A120082.

[Denominator(Bernoulli(n)/Factorial(n+1)): n in [0..50]]; // G. C. Greubel, May 01 2023

Table[Denominator[BernoulliB[n]/(n+1)!], {n,0,50}] (* G. C. Greubel, May 01 2023 *)

def A120083(n): return denominator(bernoulli(n)/factorial(n+1))
[A120083(n) for n in range(51)] # G. C. Greubel, May 01 2023

a(n) = denominator(r(n)), with r(n) = [x^n]( 1 - x/4 + Sum_{k >= 0}(B(2*k)/((2*k+1)*(2*k)!))*x^(2*k) ), |x|<2*pi. B(2*k) = A000367(k)/A002445(k) (Bernoulli numbers).

a(n) = denominator(B(n)/(n+1)!), n >= 0. See the comment on the e.g.f. D(1,x) in A120082. - Wolfdieter Lang, Jul 15 2013

A120086 Numerators of expansion of Debye function for n=4: D(4,x).

Original entry on oeis.org

1, -2, 1, 0, -1, 0, 1, 0, -1, 0, 1, 0, -691, 0, 1, 0, -3617, 0, 43867, 0, -174611, 0, 77683, 0, -236364091, 0, 657931, 0, -3392780147, 0, 1723168255201, 0, -7709321041217, 0, 151628697551, 0, -26315271553053477373

Offset: 0

Wolfdieter Lang, Jul 20 2006

Denominators are found under A120087.

See the W. Lang link under A120080 for more details on the general case D(n,x), n= 1, 2, ... D(4,x) is the e.g.f. of the rational sequence {4*B(n)/(n+4)}, n >= 0. See A227573/A227574. - Wolfdieter Lang, Jul 17 2013

			Rationals r(n): [1, -2/5, 1/18, 0, -1/1440, 0, 1/75600, 0, -1/3628800, 0, 1/167650560, 0, -691/5230697472000, ...].

Vincenzo Librandi, Table of n, a(n) for n = 0..600
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972, pp. 998, equ. 27.1.1 for n=1, with a factor (x^4)/4 extracted.
Wolfdieter Lang, Rationals r(n).

Cf. A060054. [From R. J. Mathar, Aug 07 2008]
Cf. A000367/A002445, A027641/A027642, A120097, A227573/A227574 (D(4,x) as e.g.f.). - Wolfdieter Lang, Jul 17 2013
Cf. A120080, A120081, A120082, A120083, A120084, A120085, A120087 (denominators).

[Numerator(4*(n+1)*(n+2)*(n+3)*Bernoulli(n)/Factorial(n+4)): n in [0..50]]; // G. C. Greubel, May 02 2023

r[n_]:= 4*BernoulliB[n]/((n+4)*n!); Table[r[n]//Numerator, {n,0,36}] (* Jean-François Alcover, Jun 21 2013 *)

[numerator(4*(n+1)*(n+2)*(n+3)*bernoulli(n)/factorial(n+4)) for n in range(51)] # G. C. Greubel, May 02 2023

a(n) = numerator(r(n)), with r(n) = [x^n](1 - 4*x/(2*(4+1)) + 2*Sum_{k >= 0} (B(2*k)/((k+2)*(2*k)!))*x^(2*k) ), |x| < 2*Pi. B(2*k) = A000367(k)/A002445(k) (Bernoulli numbers).

a(n) = numerator(4*B(n)/((n+4)*n!)), n >= 0, with the Bernoulli numbers B(n) = A027641(n)/A027642(n). From D(4,x) read as o.g.f. - Wolfdieter Lang, Jul 17 2013

A120087 Denominators of expansion of Debye function for n=4: D(4,x).

Original entry on oeis.org

1, 5, 18, 1, 1440, 1, 75600, 1, 3628800, 1, 167650560, 1, 5230697472000, 1, 336259123200, 1, 53353114214400000, 1, 28100018194440192000, 1, 4817145976189747200000, 1, 91657150256046735360000, 1, 11856768957122205686169600000, 1, 1396008903899788738560000000, 1

Offset: 0

Wolfdieter Lang, Jul 20 2006

From Wolfdieter Lang, Jul 17 2013: (Start)
The numerators are given in A120086.
See the link under A120080 for D(n,4) as e.g.f. of 4*B(n)/(n+4) = A227573(n)/A227574(n), n>= 0. (End)

			Rationals r(n): [1, -2/5, 1/18, 0, -1/1440, 0, 1/75600, 0, -1/3628800, 0, 1/167650560, 0, -691/5230697472000, ...].

G. C. Greubel, Table of n, a(n) for n = 0..440

Cf. A000367, A002445, A027641, A027642, A120080, A120081, A120082, A120083, A120084, A120085, A120086, A227573, A227574.

[Denominator(4*(n+1)*(n+2)*(n+3)*Bernoulli(n)/Factorial(n+4)): n in [0..50]]; // G. C. Greubel, May 02 2023

Table[Denominator[4*BernoulliB[n]/((n+4)*n!)], {n,0,50}] (* G. C. Greubel, May 02 2023 *)

[denominator(4*(n+1)*(n+2)*(n+3)*bernoulli(n)/factorial(n+4)) for n in range(51)] # G. C. Greubel, May 02 2023

a(n) = denominator(r(n)), with r(n) = [x^n](1 - 2*x/5 + 2*Sum_{k >= 0}(B(2*k)/((k+2)*(2*k)!))*x^(2*k) ), |x| < 2*Pi. B(2*k) = A000367(k)/A002445(k) (Bernoulli numbers).

a(n) = denominator(4*B(n)/((n+4)*n!)), n >= 0, with the Bernoulli numbers B(n) = A027641(n)/A027642(n). From D(4,x) read as o.g.f. - Wolfdieter Lang, Jul 17 2013

A241601 Largest divisor of A246006(n) whose prime factors are all >= n+2.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 61, 1, 277, 1, 50521, 691, 41581, 1, 199360981, 3617, 228135437, 43867, 2404879675441, 174611, 14814847529501, 77683, 69348874393137901, 236364091, 238685140977801337, 657931, 4087072509293123892361, 3392780147, 454540704683713199807

Offset: 0

Eric Chen, Dec 15 2014

nonn

Notice: Not all a(n) are 1 or primes, the first example is a(11) = 50521, it equals 19*2659.
a(2n) is a product of powers of Bernoulli irregular primes (A000928), with the exception of n = 0,1,2,3,4,5,7.
a(2n+1) is a product of powers of Euler irregular primes (A120337), with the exception of n = 0,1,2.
Conjectures: All terms are squarefree, and there are infinitely many n such that a(n) is prime.
a(n) = 1 iff n is in the set {0, 1, 2, 3, 4, 5, 6, 8, 10, 14}.
a(n) is prime for n = {7, 9, 12, 16, 17, 18, 26, 34, 36, 38, 39, 42, 49, 74, 114, 118, ...}.
All prime factors of a(n) are irregular primes (Bernoulli or Euler) and with an irregular pair to n: (61, 7), (277, 9), (19, 11), (2659, 11), (691, 12), (43, 13), (967, 13), (47, 15), (4241723, 15), (3617, 16), (228135437, 17), (43867, 18), (79, 19), (349, 19), (84224971, 19), ...
Number of ns such that a prime p divides a(n) is the irregular index of p, for example, 67 divides both a(27) and a(58), so it has irregular index two.
a(149) is the first a(n) which is not completely factored (with a 202-digit composite remaining).

Cf. A246006.
Cf. A000928, A120337.
Cf. A001067, A120082, A141590, A060054, A091912.

b[n_] := Numerator[BernoulliB[2 n]/(2 n)];
c[n_] := Numerator[SeriesCoefficient[Log[Tan[x]+1/Cos[x]], {x, 0, 2n+1}]];
a[0] = 1; a[n_] := If[EvenQ[n], b[n/2] // Abs, c[(n-1)/2]];
Table[a[n], {n, 0, 29}] (* Jean-François Alcover, Jul 03 2019 *)

a(2n) = |A001067(n)| = |A120082(2n)| = |A141590(n)| = |A060054(n)|.

a(2n+1) = A091912(n).

A120084 Numerators of expansion for Debye function for n=2: D(2,x).

Original entry on oeis.org

1, -1, 1, 0, -1, 0, 1, 0, -1, 0, 1, 0, -691, 0, 1, 0, -3617, 0, 43867, 0, -174611, 0, 77683, 0, -236364091, 0, 657931, 0, -3392780147, 0, 1723168255201, 0, -7709321041217, 0, 151628697551, 0, -26315271553053477373, 0, 154210205991661, 0, -261082718496449122051

Offset: 0

Wolfdieter Lang, Jul 20 2006

Denominators are found under A120085.

This sequence appears to coincide with A120082.

			Rationals r(n): [1, -1/3, 1/24, 0, -1/2160, 0, 1/120960, 0, -1/6048000, 0, 1/287400960, ...].

G. C. Greubel, Table of n, a(n) for n = 0..500
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, pp. 998, equ. 27.1.1 for n=1, with a factor (x^2)/2 extracted.
Wolfdieter Lang, Rationals r(n).

Cf. A000367, A002445, A120080, A120081, A120082, A120083, A120085, A120086, A120087.

[Numerator(2*(n+1)*Bernoulli(n)/Factorial(n+2)): n in [0..50]]; // G. C. Greubel, May 02 2023

max = 38; Numerator[CoefficientList[Integrate[Normal[Series[(2*(t^2/(Exp[t]-1)))/x^2, {t, 0, max}]], {t, 0, x}], x]] (* Jean-François Alcover, Oct 04 2011 *)
Table[Numerator[2*(n+1)*BernoulliB[n]/(n+2)!], {n,0,50}] (* G. C. Greubel, May 02 2023 *)

[numerator(2*(n+1)*bernoulli(n)/factorial(n+2)) for n in range(51)] # G. C. Greubel, May 02 2023

a(n) = numerator(r(n)), with r(n) = [x^n]( 1 - x/3 + Sum_{k >= 1} (B(2*k)/((k+1)*(2*k)!))*x^(2*k) ), |x|<2*Pi. B(2*k) = A000367(k)/A002445(k) (Bernoulli numbers).

a(n) = numerator(2*B(n)/((n+2)*n!)), n >= 0. See the comment on the e.g.f. D(2,x) in A120085. - Wolfdieter Lang, Dec 03 2022

A111008 a(n) = A000367(n)/A141590(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 5, 1, 7, 1, 1, 1, 11, 1, 13, 7, 5, 1, 17, 1, 19, 1, 1, 11, 23, 1, 25, 13, 1, 7, 29, 1, 31, 1, 11, 629, 35, 1, 37, 19, 13, 1, 41, 1, 43, 11, 5, 23, 47, 1, 49, 1, 1003, 481, 53, 1, 5, 7, 19, 29, 59, 1, 61, 2077, 103, 1, 65, 11, 67, 17, 23, 259, 71, 1, 73, 37, 25, 2489, 77

Offset: 0

Paul Curtz, Aug 25 2008

nonn

Jeppe Stig Nielsen, Table of n, a(n) for n = 0..10000

See A141517.

Cf. A300711.

A120082 := proc(n) local b; if n = 0 then b := 1 ; elif n = 1 then b := -1/4 ; elif type(n,'odd') then b := 0; else b := bernoulli(n)/(n+1)! ; fi; numer(b) ; end:
A141590 := proc(n) A120082(2*n) ; end: A000367 := proc(n) numer(bernoulli(2*n)) ; end:
A111008 := proc(n) A000367(n)/A141590(n) ; end: seq(A111008(n),n=0..120) ; # R. J. Mathar, Sep 03 2009

upto(N)=bernvec(N);forstep(n=0,2*N,2,print1(gcd(numerator(bernfrac(n)), (n+1)!),", ")) \\ Jeppe Stig Nielsen, Jun 22 2023

Edited and extended by R. J. Mathar, Sep 03 2009

A120085 Denominators of expansion for Debye function for n=2: D(2,x).

Original entry on oeis.org

1, 3, 24, 1, 2160, 1, 120960, 1, 6048000, 1, 287400960, 1, 9153720576000, 1, 597793996800, 1, 96035605585920000, 1, 51090942171709440000, 1, 8831434289681203200000, 1, 169213200472701665280000, 1, 22019713777512667702886400000, 1, 2605883287279605645312000000

Offset: 0

Wolfdieter Lang, Jul 20 2006

Numerators are found under A120084.
D(2,x) := (2/x^2)*Integral_{0..x} t^2/(exp(t)-1) dt is the e.g.f. of 2*B(n)/(n+2), n>=0, with the Bernoulli numbers B(n) = A027641(n)/A027642(n). Proof by using the e.g.f. for {k*B(k-1)} (with 0 for k=0) and integrating termwise (allowed for |x| <= r < rho with small enough rho).
See the Abramowitz-Stegun link for the integral and an expansion. - Wolfdieter Lang, Jul 16 2013

			Rationals r(n): [1, -1/3, 1/24, 0, -1/2160, 0, 1/120960, 0, -1/6048000, 0, 1/287400960,...].

G. C. Greubel, Table of n, a(n) for n = 0..445
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, pp. 998, equ. 27.1.1 for n=2, multiplied by 2/x^2.

Cf. A000367/A002445, A027641/A027642, A120080/A120081 (D(3,x) expansion), A120082/A120083 (D(1,x) expansion), A120084, A120086, A120087.

[Denominator(2*(n+1)*Bernoulli(n)/Factorial(n+2)): n in [0..50]]; // G. C. Greubel, May 02 2023

max = 25; Denominator[CoefficientList[Integrate[Normal[Series[(2*(t^2/(Exp[t]-1)))/x^2, {t, 0, max}]], {t, 0, x}], x]](* Jean-François Alcover, Oct 04 2011 *)
Table[Denominator[2*(n+1)*BernoulliB[n]/(n+2)!], {n,0,50}] (* G. C. Greubel, May 02 2023 *)

[denominator(2*(n+1)*bernoulli(n)/factorial(n+2)) for n in range(51)] # G. C. Greubel, May 02 2023

a(n) = denominator(r(n)), with r(n) = [x^n]( 1 - x/3 + Sum_{k >= 1} (B(2*k)/((k+1)*(2*k)!))*x^(2*k) ), |x|<2*pi. B(2*k) = A000367(k)/A002445(k) (Bernoulli numbers).

a(n) = denominator(2*B(n)/((n+2)*n!)), n >= 0. See the comment on the e.g.f. D(2,x) above. - Wolfdieter Lang, Jul 16 2013

cp's OEIS Frontend

A141590 a(n) = numerator of Bernoulli(2*n)/(2*n + 1)!. Bisection of A120082.

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A141588 Numerators of expansion for Debye function (D(1,x)) A120082 with 1's instead of 0's.

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A060054 Numerators of numbers appearing in the Euler-Maclaurin summation formula.

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A120083 Denominators of expansion for Debye function for n=1: D(1,x).

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A120086 Numerators of expansion of Debye function for n=4: D(4,x).

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A120087 Denominators of expansion of Debye function for n=4: D(4,x).

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A241601 Largest divisor of A246006(n) whose prime factors are all >= n+2.

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A141590 a(n) = numerator of Bernoulli(2n)/(2n + 1)!. Bisection of A120082.