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.

A117398 Matrix log of triangle A117396.

Original entry on oeis.org

0, 1, 0, 0, 2, 0, -1, 2, 3, 0, -3, 4, 5, 4, 0, -9, 14, 15, 9, 5, 0, -33, 68, 65, 34, 14, 6, 0, -153, 404, 359, 174, 63, 20, 7, 0, -873, 2804, 2375, 1098, 371, 104, 27, 8, 0, -5913, 22244, 18215, 8154, 2639, 692, 159, 35, 9, 0, -46233, 198644, 158615, 69354, 21791, 5480, 1179, 230, 44, 10, 0
Offset: 0

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Author

Paul D. Hanna, Mar 11 2006

Keywords

Comments

Column 0 contains negative of sequence A007489.

Examples

			Triangle begins:
      0;
      1,     0;
      0,     2,     0;
     -1,     2,     3,    0;
     -3,     4,     5,    4,    0;
     -9,    14,    15,    9,    5,   0;
    -33,    68,    65,   34,   14,   6,   0;
   -153,   404,   359,  174,   63,  20,   7,  0;
   -873,  2804,  2375, 1098,  371, 104,  27,  8,  0;
  -5913, 22244, 18215, 8154, 2639, 692, 159, 35,  9,  0;
		

Crossrefs

Cf. A117396, A007489 (column 0), A117399 (column 1).

Programs

  • Mathematica
    m=12;
    M= Table[If[k>n-1, 0, If[k==n-1, n, -1]], {n,0,m+1}, {k,0,m+1}];
    T:= T= Sum[MatrixPower[M, j]/j, {j,m+1}];
    Table[T[[n+1, k+1]], {n,0,m}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 06 2022 *)
  • PARI
    {T(n,k)=local(M=matrix(n+4,n+4,r,c,if(r>=c,if(r==c+1,-c,1))), L=sum(m=1,n+4,(M^0-M)^m/m));L[n+1,k+1]}

Formula

From G. C. Greubel, Sep 06 2022: (Start)
T(n, n) = 0.
T(n, n-1) = A000027(n).
T(n, n-2) = A000096(n-2).
T(n, 0) = n*[n<2] - A007489(n-2)*[n>1].
T(n, 1) = 0 + 2*A117399(n-1)*[n>1].
Sum_{k=0..n} T(n, k) = A003422(n). (End)

A117397 Column 3 of triangle A117396.

Original entry on oeis.org

1, 4, 19, 109, 739, 5779, 51139, 504739, 5494339, 65369539, 843747139, 11741033539, 175200329539, 2790549065539, 47251477577539, 847548190793539, 16053185741897539, 320165936763977539, 6706533708227657539, 147206624680428617539, 3378708717041050697539
Offset: 0

Views

Author

Paul D. Hanna, Mar 11 2006

Keywords

Comments

Equals the partial sums of column 3 of triangle A092582.

Examples

			G.f.: A(x) = 1 + 4*x + 19*x^2 + 109*x^3 + 739*x^4 + 5779*x^5 + 51139*x^6 + 504739*x^7 + 5494339*x^8 + 65369539*x^9 + 843747139*x^10 + ...
		

Crossrefs

Cf. A117396 (triangle), A014288 (column 1), A056199 (column 2), A003422 (row sums).

Programs

  • Magma
    [(&+[Factorial(j): j in [2..n+3]])/8: n in [0..30]]; // G. C. Greubel, Sep 05 2022
    
  • Maple
    a:=n->sum(j!/8,j=2..n): seq(a(n), n=3..21); # Zerinvary Lajos, Jan 08 2007
  • Mathematica
    Table[Sum[i!/8, {i, 2, n}], {n, 3, 21}] (* Zerinvary Lajos, Jul 12 2009 *)
  • PARI
    {a(n)=1+sum(k=4,n+3,k!)*3/4!}
    for(n=0,25,print1(a(n),", "))
    
  • SageMath
    [sum(factorial(j) for j in (2..n+3))/8 for n in (0..30)] # G. C. Greubel, Sep 05 2022

Formula

G.f. satisfies A(x) = (1-x)/(1 - 5*x + 5*x^2) * (1 + x^2*A'(x)).
a(n) = 1 + Sum_{k=4..n+3} k!*3/4! for n > 0, with a(0)=1.
G.f.: W(0)/(8*x*(1-x)) -1/(4*x), where W(k) = 1 + 1/( 1 - x*(k+3)/( x*(k+3) + 1/W(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Aug 20 2013
G.f.: (Sum_{n>=0} (n+2)!*x^n)/(8*x*(1-x)) - 1/(4*x). - Sergei N. Gladkovskii, Aug 20 2013
a(n) = (1/8)*(A007489(n+3) - 1) = (1/8)*(A003422(n+4) - 2). - G. C. Greubel, Sep 05 2022

A117399 Column 1 (divided by 2) of triangle A117398, which is the matrix log of A117396.

Original entry on oeis.org

1, 1, 2, 7, 34, 202, 1402, 11122, 99322, 986362, 10784122, 128720122, 1665516922, 23220588922, 347025670522, 5534133996922, 93802153836922, 1683934185324922, 31917365573484922, 636941680764780922, 13348854673487724922
Offset: 1

Views

Author

Paul D. Hanna, Mar 11 2006

Keywords

Crossrefs

Programs

  • Mathematica
    m=42;
    M= Table[If[k>n-1, 0, If[k==n-1, n, -1]], {n,0,m+1}, {k,0,m+1}];
    T:= T= Sum[MatrixPower[M, j]/j, {j,m+1}];
    Table[T[[n+1, 2]]/2, {n,2,30}] (* G. C. Greubel, Sep 06 2022 *)
  • PARI
    {a(n)=local(M=matrix(n+4,n+4,r,c,if(r>=c,if(r==c+1,-c,1))), L=sum(m=1,n+4,(M^0-M)^m/m));L[n+2,2]/2}
Showing 1-3 of 3 results.