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.

A060083 Coefficients of even-indexed Euler polynomials (rising powers without zeros).

Original entry on oeis.org

1, -1, 1, 1, -2, 1, -3, 5, -3, 1, 17, -28, 14, -4, 1, -155, 255, -126, 30, -5, 1, 2073, -3410, 1683, -396, 55, -6, 1, -38227, 62881, -31031, 7293, -1001, 91, -7, 1, 929569, -1529080, 754572, -177320, 24310, -2184, 140, -8, 1, -28820619
Offset: 0

Views

Author

Wolfdieter Lang, Mar 29 2001

Keywords

Comments

E(2*n,1/2)*(-4)^n = A000364(n) (signless Euler numbers without zeros).

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 809.

Crossrefs

A060082 (falling powers).
Matrix inverse is A102054. Column 0 is A001469 (Genocchi numbers).

Programs

  • Mathematica
    t[n_, k_] := Binomial[2*n, 2*k]*2*(n - k)*EulerE[2*(n - k) - 1, 0]/(2*k + 1); t[n_, n_] = 1; Table[t[n, k], {n, 0, 9}, {k, 0, n }] // Flatten (* Jean-François Alcover, Jul 03 2013 *)
  • PARI
    {T(n,k)=local(X=x+x*O(x^(2*n)),Y=y+y*O(y^(2*k+1))); (2*n)!*polcoeff(polcoeff((cosh(X*Y)*(Y-1)+ exp(X*Y)/(exp(X)+1)+exp(-X*Y)/(exp(-X)+1))/Y,2*n,x),2*k,y)} (Hanna)

Formula

E(2*n, x)= sum(a(n, m)*x^(2*m+1), m=0..n-1) + x^(2*n), n >= 1; E(0, x)=1.
T(n, k) = A102054(n, k+1) - A102054(n+1, k+1), where A102054 is matrix inverse. E.g.f.: A(x^2, y^2) = [cosh(xy)*(y-1) + exp(xy)/(exp(x)+1) + exp(-xy)/(exp(-x)+1)]/y. - Paul D. Hanna, Dec 28 2004
T(n,k) = 1/(2*k+1)*binomial(2*n,2*k)*A001469(n-k) for 0 <= k <= n-1.
Let F(n,x) = Sum_{k=0..n-1} binomial(n-k-1,k)*x^k be a Fibonacci polynomial (see A011973 for coefficients). Then F(2*n,x) = -Sum_{k=0..n-1} T(n,k)*F(2*k+1,x). For example, F(8,x) = -17*F(1,x) + 28*F(3,x) - 14*F(5,x) + 4*F(7,x). See Cigler, Corollary 1.3. - Peter Bala, Mar 14 2012

A076552 a(n) = (-1)^(n+1)/3/(2n+1) * Sum_{k=0..n} 16^k*B(2k)*C(2n+1,2k) where B(k) denotes the k-th Bernoulli number.

Original entry on oeis.org

1, 1, 21, 461, 16841, 900921, 66453661, 6463837381, 801626558481, 123457062745841, 23116291464379301, 5171511387852362301, 1362357503097707964121, 417419880467876621822761, 147181297749674368184560941, 59173130526513096478888263221
Offset: 1

Views

Author

Benoit Cloitre, Oct 19 2002

Keywords

Comments

Terms are of form 10k+1.

Crossrefs

Programs

  • Mathematica
    max = 28; CoefficientList[Series[1/3-2*Sin[x]/(3*Tan[2*x]), {x, 0, max}], x^2] * Range[0, max, 2]! // Rest (* Jean-François Alcover, Apr 08 2015, after Vladimir Kruchinin *)
  • PARI
    a(n)=(-1)^(n+1)/3/(2*n+1)*sum(k=0,n,16^k*bernfrac(2*k)*binomial(2*n+1,2*k))

Formula

From Peter Bala, Jul 26 2013: (Start)
It appears that a(n) = 1/3*(A000364(n) - 2*(-1)^n). See A060082.
Conjectural e.g.f. with offset 0 (checked up to a(14)): 1/3*(2 - cos(x)^2 + 2*cos(x)^4)/cos(x)^3 = 1 + x^2/2! + 21*x^4/4! + 461*x^6/6! + .... (End)
G.f.: 1/(Q(0)*3*x) + 2/(3*x^2*(1+x)) - 2/(3*x^2) + 1/(3*x), where Q(k) = 1 - x*(k+1)^2/Q(k+1) ; (continued fraction). - Sergei N. Gladkovskii, Sep 19 2013
a(n) = (2n)! * [x^(2n)] 1/3-2*sin(x)/(3*tan(2*x)). - Vladimir Kruchinin, Apr 08 2015
Conjecture: a(n) = -1/3*(-4)^n*E(2*n,-1/2), where E(n,x) is the n-th Euler polynomial. - Peter Bala, Sep 25 2016

A004173 Triangle of coefficients of Euler polynomials E_2n(x) (exponents in decreasing order).

Original entry on oeis.org

1, 1, -1, 0, 1, -2, 0, 1, 0, 1, -3, 0, 5, 0, -3, 0, 1, -4, 0, 14, 0, -28, 0, 17, 0, 1, -5, 0, 30, 0, -126, 0, 255, 0, -155, 0, 1, -6, 0, 55, 0, -396, 0, 1683, 0, -3410, 0, 2073, 0, 1, -7, 0, 91, 0, -1001, 0, 7293, 0, -31031, 0, 62881, 0, -38227, 0, 1, -8, 0, 140, 0
Offset: 0

Views

Author

N. J. A. Sloane, corrected Jan 09 2007

Keywords

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 809.

Crossrefs

Programs

  • Mathematica
    Flatten[Table[Reverse @ CoefficientList[EulerE[2n, x], x] , {n, 0, 8}]] (* Jean-François Alcover, Jul 21 2011 *)
Showing 1-3 of 3 results.