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.

Previous Showing 11-15 of 15 results.

A001237 Differences of reciprocals of unity.

Original entry on oeis.org

31, 3661, 1217776, 929081776, 1413470290176, 3878864920694016, 17810567950611972096, 129089983180418186674176, 1409795030885143760732160000, 22335321387514981111936450560000, 497400843208278958640564703068160000, 15161356456130244705175927906904309760000
Offset: 1

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Author

Keywords

References

  • F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 228.
  • 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

Column 4 in triangle A008969.

Programs

  • Mathematica
    a[n_] := -(Factorial[n + 1]^4)*Sum[(-1)^k Binomial[n + 1, k]/k^4, {k, 1, n + 1}];Table[a[n],{n,14}] (* James C. McMahon, Dec 12 2023 *)
  • PARI
    a(n)=-(n+1)!^4*sum(k=1,n+1,(-1)^k*binomial(n+1,k)/k^4) \\ Charles R Greathouse IV, Mar 29 2012

Formula

a(n) = (n + 1)!^4/480*(20*Psi(n + 2)^4 + 80*gamma*Psi(n + 2)^3 - 120*Psi(n + 2)^2*Psi(1, n + 2) + 20*Pi^2*Psi(n + 2)^2 + 120*gamma^2*Psi(n + 2)^2 - 240*gamma*Psi(n + 2)*Psi(1, n + 2) + 80*Psi(n + 2)*Psi(2, n + 2) + 60*Psi(1, n + 2)^2 + 40*gamma*Pi^2*Psi(n + 2) + 160*Zeta(3)*Psi(n + 2) + 80*gamma^3*Psi(n + 2) - 20*Pi^2*Psi(1, n + 2) - 120*gamma^2*Psi(1, n + 2) + 80*gamma*Psi(2, n + 2) - 20*Psi(3, n + 2) + 160*gamma*Zeta(3) + 3*Pi^4 + 20*gamma^4 + 20*gamma^2*Pi^2). - Vladeta Jovovic, Aug 10 2002
a(n) = (n+1)!^4 * Sum_{i=1..n+1} Sum_{j=1..i} Sum_{k=1..j} Sum_{l=1..k} 1/(ijkl).
a(n) = (n+1)!^4 * Sum_{k=1..n+1} (-1)^(k+1)*C(n+1,k)/k^4. - Sean A. Irvine, Mar 29 2012

Extensions

More terms from Vladeta Jovovic, Aug 10 2002
a(11)-a(12) from James C. McMahon, Dec 12 2023

A111887 Seventh column of triangle A112492 (inverse scaled Pochhammer symbols).

Original entry on oeis.org

1, 13068, 104587344, 673781602752, 3878864920694016, 21006340945438768128, 110019668725577574273024, 565858042127972959667208192, 2882220940619488483325345857536, 14605752814655604919042956624396288
Offset: 0

Views

Author

Wolfdieter Lang, Sep 12 2005

Keywords

Comments

Also continuation of family of differences of reciprocals of unity. See A001242, A111886 and triangle A008969.

Crossrefs

Also right-hand column 6 in triangle A008969.

Programs

  • Magma
    A111887:= func< n | (-1)*Factorial(7)^n*(&+[(-1)^j*Binomial(7,j)/j^n : j in [1..7]]) >;
    [A111887(n): n in [0..30]]; // G. C. Greubel, Jul 24 2023
    
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, (k+1)^(n-k)*T[n-1,k-1] + k!*T[n-1,k]]; (* T = A112492 *)
    Table[T[n+6,6], {n,0,30}] (* G. C. Greubel, Jul 24 2023 *)
  • PARI
    a(n) = -((7!)^n)*sum(j=1, 7, ((-1)^j)*binomial(7, j)/j^n); \\ Michel Marcus, Apr 28 2020
    
  • SageMath
    @CachedFunction
    def T(n,k): # T = A112492
        if (k==0 or k==n): return 1
        else: return (k+1)^(n-k)*T(n-1,k-1) + factorial(k)*T(n-1,k)
    def A111887(n): return T(n+6,6)
    [A111887(n) for n in range(31)] # G. C. Greubel, Jul 24 2023

Formula

G.f.: 1/Product_{j=1..7} 1-7!*x/j.
a(n) = -((7!)^n) * Sum_{j=1..7} (-1)^j*binomial(7, j)/j^n, n>=0.
a(n) = A112492(n+6, 7), n>=0.

A111888 Eighth column of triangle A112492 (inverse scaled Pochhammer symbols).

Original entry on oeis.org

1, 109584, 7245893376, 381495483224064, 17810567950611972096, 778101042571221893382144, 32762625292956765972873609216, 1351813956241264848815287984717824
Offset: 0

Views

Author

Wolfdieter Lang, Sep 12 2005

Keywords

Comments

Also continuation of family of Differences of reciprocals of unity. See A001242, A111887 and triangle A008969.

Crossrefs

Also right-hand column 7 in triangle A008969.

Programs

  • Magma
    A111888:= func< n | (-1)*Factorial(8)^n*(&+[(-1)^j*Binomial(8,j)/j^n : j in [1..8]]) >;
    [A111888(n): n in [0..30]]; // G. C. Greubel, Jul 24 2023
    
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, (k+1)^(n-k)*T[n-1,k-1] +k!*T[n-1,k]]; (* T = A112492 *)
    Table[T[n+7,7], {n,0,30}] (* G. C. Greubel, Jul 24 2023 *)
  • PARI
    a(n) = -((8!)^n)*sum(j=1, 8, ((-1)^j)*binomial(8, j)/j^n); \\ Michel Marcus, Apr 28 2020
    
  • SageMath
    @CachedFunction
    def T(n,k): # T = A112492
        if (k==0 or k==n): return 1
        else: return (k+1)^(n-k)*T(n-1,k-1) + factorial(k)*T(n-1,k)
    def A111888(n): return T(n+7,7)
    [A111888(n) for n in range(31)] # G. C. Greubel, Jul 24 2023

Formula

G.f.: 1/Product_{j=1..8} 1-8!*x/j.
a(n) = -((8!)^n) * Sum_{j=1..8} (-1)^j*binomial(8, j)/j^n, n>=0.
a(n) = A112492(n+7, 8), n>=0.

A103879 Square array T(n,k) read by antidiagonals: numerators of Stirling numbers of first kind with negative argument S1(-n,k), n,k>=0.

Original entry on oeis.org

1, 1, 0, 1, -1, 0, 1, -3, 1, 0, 1, -11, 7, -1, 0, 1, -25, 85, -15, 1, 0, 1, -137, 415, -575, 31, -1, 0, 1, -49, 12019, -5845, 3661, -63, 1, 0, 1, -121, 13489, -874853, 76111, -22631, 127, -1, 0, 1, -761, 726301, -336581, 58067611, -952525, 137845, -255, 1
Offset: 0

Views

Author

Ralf Stephan, Feb 20 2005

Keywords

Examples

			1, 0, 0, 0, 0, 0,
1, -1, 1, -1, 1, -1,
1/2, -3/4, 7/8, -15/16, 31/32, -63/64,
1/6, -11/36, 85/216, -575/1296, 3661/7776, -22631/46656,
1/24,-25/288,415/3456,-5845/41472,76111/497664,-952525/5971968,
		

Crossrefs

Denominators are in A103880. Cf. A008969.

Programs

  • PARI
    T(n,k)=numerator(1/n!*polcoeff(Ser(1/prod(i=1,n,1+x/i)),k))

Formula

T(n, k) = (-1)^(k+1) * Sum[i=1..n, C(n, i)*(-1)^i*i^(-k) ].
G.f. of n-th row: 1/n! * 1/Prod[i=1..n, 1+x/i ].

A103880 Square array T(n,k) read by antidiagonals: denominators of Stirling numbers of first kind with negative argument S1(-n,k), n,k>=0.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 6, 4, 1, 1, 24, 36, 8, 1, 1, 120, 288, 216, 16, 1, 1, 720, 7200, 3456, 1296, 32, 1, 1, 5040, 14400, 432000, 41472, 7776, 64, 1, 1, 40320, 235200, 2592000, 25920000, 497664, 46656, 128, 1, 1, 362880, 11289600, 889056000, 51840000
Offset: 0

Views

Author

Ralf Stephan, Feb 20 2005

Keywords

Examples

			1, 0, 0, 0, 0, 0,
1, -1, 1, -1, 1, -1,
1/2, -3/4, 7/8, -15/16, 31/32, -63/64,
1/6, -11/36, 85/216, -575/1296, 3661/7776, -22631/46656,
1/24,-25/288,415/3456,-5845/41472,76111/497664,-952525/5971968,
		

Crossrefs

Numerators are in A103879. Cf. A008969.

Programs

  • PARI
    T(n,k)=denominator(1/n!*polcoeff(Ser(1/prod(i=1,n,1+x/i)),k))

Formula

T(n, k) = (-1)^(k+1) * Sum[i=1..n, C(n, i)*(-1)^i*i^(-k) ].
G.f. of n-th row: 1/n! * 1/Prod[i=1..n, 1+x/i ].
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