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 1-6 of 6 results.

A111942 Column 0 of the matrix logarithm (A111941) of triangle A111940, which shifts columns left and up under matrix inverse; these terms are the result of multiplying the element in row n by n!.

Original entry on oeis.org

0, 1, -1, 1, -2, 4, -12, 36, -144, 576, -2880, 14400, -86400, 518400, -3628800, 25401600, -203212800, 1625702400, -14631321600, 131681894400, -1316818944000, 13168189440000, -144850083840000, 1593350922240000, -19120211066880000
Offset: 0

Views

Author

Paul D. Hanna, Aug 23 2005

Keywords

Comments

Signed version of A010551, with leading zero.

Examples

			E.g.f.: A(x) = x - (1/2!)*x^2 + (1/3!)*x^3 - (2/4!)*x^4 + (4/5!)*x^5 - (12/6!)*x^6 + (36/7!)*x^7 - (144/8!)*x^8 + (576/9!)*x^9 + ... where A(x)*A(-x) = -arccos(1-x^2/2)^2.

Crossrefs

Cf. A111940 (triangle), A111941 (matrix log), A110505 (variant), A010551 (unsigned).

Programs

  • PARI
    {a(n,q=-1)=local(A=Mat(1),B);if(n<0,0, for(m=1,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=1,if(j==1,B[i,j]=(A^q)[i-1,1], B[i,j]=(A^q)[i-1,j-1]));));A=B); B=sum(i=1,#A,-(A^0-A)^i/i);return(n!*B[n+1,1]))}

Formula

a(n) = (-1)^(n-1) * floor((n-1)/2)! * floor(n/2)! for n > 0, with a(0)=0.
E.g.f.: A(x) = (1-x/2)/sqrt(1-x^2/4)*arccos(1-x^2/2).
G.f.: x*G(0) where G(k) = 1 - (k+1)*x/(1 - x*(k+1)/(x*(k+1) - 1/G(k+1) )); (continued fraction, 3-step). - Sergei N. Gladkovskii, Nov 28 2012
G.f.: G(0)*x/2, where G(k) = 1 + 1/(1 - x*(k+1)/(x*(1*k+1) - 1/(1 + 1/(1 - x*(k+1)/(x*(1*k+1) - 1/G(k+1)))))); (continued fraction). - Sergei N. Gladkovskii, Jun 20 2013
G.f.: x/G(0), where G(k) = 1 - x*(k+1)/(x*(k+1) - 1/(1 - x*(k+1)/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Aug 07 2013
Conjecture: 4*a(n) + 2*a(n-1) - (n-1)*(n-2)*a(n-2) = 0, n > 2. - R. J. Mathar, Nov 25 2015

A111811 Column 0 of the matrix logarithm (A111810) of triangle A098539, which shifts columns left and up under matrix square; these terms are the result of multiplying the element in row n by n!.

Original entry on oeis.org

0, 1, 2, 10, 88, 1096, 11856, -402480, -1891968, 36024603264, 359905478400, -53686393014816000, -644141701131494400, 1790653231402788752593920, 25068910772059830672353280, -1280832036591718248285105113241600
Offset: 0

Views

Author

Paul D. Hanna, Aug 22 2005

Keywords

Comments

Let q=2; the g.f. of column k of A098539^m (matrix power m) is: 1 + Sum_{n>=1} (m*q^k)^n/n! * Product_{j=0..n-1} A(q^j*x).

Examples

			A(x) = x + 2/2!*x^2 + 10/3!*x^3 + 88/4!*x^4 + 1096/5!*x^5 +...
where e.g.f. A(x) satisfies:
x = A(x) - A(x)*A(2*x)/2! + A(x)*A(2*x)*A(2^2*x)/3! - A(x)*A(2*x)*A(2^2*x)*A(2^3*x)/4! + ...
also:
x/(1+x) = A(x) - 2*A(x)*A(2*x)/2! + 2^2*A(x)*A(2*x)*A(2^2*x)/3! - 2^3*A(x)*A(2*x)*A(2^2*x)*A(2^3*x)/4! +...
Let G(x) be the g.f. of A002449 (column 1 of A098539), then
(G(x)-1)/x = 1 + 2*x + 6*x^2 + 26*x^3 + 166*x^4 + 1626*x^5 +...
= 1 + 2*A(x) + 2^2*A(x)*A(2*x)/2! + 2^3*A(x)*A(2*x)*A(2^2*x)/3! + 2^4*A(x)*A(2*x)*A(2^2*x)*A(2^3*x)/4! +...

Crossrefs

Cf. A111810 (matrix log), A098539 (triangle), A002449, A111814 (variant), A111941 (q=-1), A111843 (q=3), A111848 (q=4).

Programs

  • PARI
    {a(n,q=2)=local(A=x+x*O(x^n));for(i=1,n, A=x/(1+sum(j=1,n,prod(k=1,j,-subst(A,x,q^k*x))/(j+1)!))); return(n!*polcoeff(A,n))}

Formula

E.g.f. satisfies: x = -Sum_{n>=1} Prod_{j=0..n-1} -A(2^j*x)/(j+1), also: x/(1+x) = Sum_{n>=1} (-2)^(n-1)*Prod_{j=0..n-1} A(2^j*x)/(j+1).

A111843 Matrix log of triangle A111840, which shifts columns left and up under matrix cube; these terms are the result of multiplying each element in row n and column k by (n-k)!.

Original entry on oeis.org

0, 1, 0, 3, 3, 0, 27, 9, 9, 0, 486, 81, 27, 27, 0, 7776, 1458, 243, 81, 81, 0, -2423196, 23328, 4374, 729, 243, 243, 0, -97338996, -7269588, 69984, 13122, 2187, 729, 729, 0, 5883879500784, -292016988, -21808764, 209952, 39366, 6561, 2187, 2187, 0
Offset: 0

Views

Author

Paul D. Hanna, Aug 23 2005

Keywords

Comments

Column k equals 3^k multiplied by column 0 (A111844) when ignoring zeros above the diagonal.

Examples

			Matrix log of A111840, with factorial denominators, begins:
0;
1/1!, 0;
3/2!, 3/1!, 0;
27/3!, 9/2!, 9/1!, 0;
486/4!, 81/3!, 27/2!, 27/1!, 0;
7776/5!, 1458/4!, 243/3!, 81/2!, 81/1!, 0;
-2423196/6!, 23328/5!, 4374/4!, 729/3!, 243/2!, 243/1!, 0;

Crossrefs

Cf. A111840 (triangle), A111844 (column 0), A111815 (variant), A111941 (q=-1), A111810 (q=2), A111848 (q=4).

Programs

  • PARI
    T(n,k,q=3)=local(A=Mat(1),B);if(n

Formula

T(n, k) = 3^k*T(n-k, 0) = 3^k*A111844(n-k) for n>=k>=0.

A111844 Column 0 of the matrix logarithm (A111843) of triangle A111840, which shifts columns left and up under matrix cube; these terms are the result of multiplying the element in row n by n!.

Original entry on oeis.org

0, 1, 3, 27, 486, 7776, -2423196, -97338996, 5883879500784, 548540050402080, -1737375315124971951360, -405928706169160555680960, 60788545124934395018363657569920, 36207408592259278909089966337224960, -237458310218887960183820317532070376189904640
Offset: 0

Views

Author

Paul D. Hanna, Aug 23 2005

Keywords

Comments

Let q=3; the g.f. of column k of A111840^m (matrix power m) is: 1 + Sum_{n>=1} (m*q^k)^n/n! * Product_{j=0..n-1} A(q^j*x).

Examples

			E.g.f. A(x) = x + 3/2!*x^2 + 27/3!*x^3 + 486/4!*x^4 + 7776/5!*x^5
- 2423196/6!*x^6 - 97338996/7!*x^7 +...
where A(x) satisfies:
x = A(x) - A(x)*A(3*x)/2! + A(x)*A(3*x)*A(3^2*x)/3!
- A(x)*A(3*x)*A(3^2*x)*A(3^3*x)/4! + ...
also:
Let G(x) be the g.f. of A111841 (column 0 of A111840), then
G(x) = 1 + x + 3*x^2 + 18*x^3 + 216*x^4 + 5589*x^5 + 336555*x^6 +...
= 1 + A(x) + A(x)*A(3*x)/2! + A(x)*A(3*x)*A(3^2*x)/3!
+ A(x)*A(3*x)*A(3^2*x)*A(3^3*x)/4! +...

Crossrefs

Cf. A111843 (matrix log), A111840 (triangle), A111841, A111816 (variant), A111941 (q=-1), A111843 (q=3), A111848 (q=4).

Programs

  • PARI
    {a(n,q=3)=local(A=Mat(1),B);if(n<0,0, for(m=1,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=1,if(j==1,B[i,j]=(A^q)[i-1,1], B[i,j]=(A^q)[i-1,j-1]));));A=B); B=sum(i=1,#A,-(A^0-A)^i/i);return(n!*B[n+1,1]))}

Formula

E.g.f. satisfies: x = -Sum_{n>=1} Prod_{j=0..n-1} -A(3^j*x)/(j+1).

A111810 Matrix log of triangle A098539, which shifts columns left and up under matrix square; these terms are the result of multiplying each element in row n and column k by (n-k)!.

Original entry on oeis.org

0, 1, 0, 2, 2, 0, 10, 4, 4, 0, 88, 20, 8, 8, 0, 1096, 176, 40, 16, 16, 0, 11856, 2192, 352, 80, 32, 32, 0, -402480, 23712, 4384, 704, 160, 64, 64, 0, -1891968, -804960, 47424, 8768, 1408, 320, 128, 128, 0, 36024603264, -3783936, -1609920, 94848, 17536, 2816, 640, 256, 256, 0
Offset: 0

Views

Author

Paul D. Hanna, Aug 22 2005

Keywords

Comments

Column k equals 2^k times column 0 (A111811) when ignoring zeros above the diagonal.

Examples

			Matrix log of A098539, with factorial denominators, begins:
0;
1/1!, 0;
2/2!, 2/1!, 0;
10/3!, 4/2!, 4/1!, 0;
88/4!, 20/3!, 8/2!, 8/1!, 0;
1096/5!, 176/4!, 40/3!, 16/2!, 16/1!, 0;
11856/6!, 2192/5!, 352/4!, 80/3!, 32/2!, 32/1!, 0; ...

Crossrefs

Cf. A098539 (triangle), A111811 (column 0), A111813 (variant), A111941 (q=-1), A111843 (q=3), A111848 (q=4).

Programs

  • PARI
    T(n,k,q=2)=local(A=Mat(1),B);if(n

Formula

T(n, k) = 2^k*T(n-k, 0) = 2^k*A111811(n-k) for n>=k>=0.

A111940 Triangle P, read by rows, that satisfies [P^-1](n,k) = P(n+1,k+1) for n >= k >= 0, with P(k,k)=1 and P(k+1,1)=P(k+1,0) for k >= 0, where [P^-1] denotes the matrix inverse of P.

Original entry on oeis.org

1, 1, 1, -1, -1, 1, 0, 0, 1, 1, 0, 0, -1, -1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, -1, -1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, -1, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1
Offset: 0

Views

Author

Paul D. Hanna, Aug 23 2005

Keywords

Examples

			Triangle P begins:
   1;
   1,  1;
  -1, -1,  1;
   0,  0,  1,  1;
   0,  0, -1, -1,  1;
   0,  0,  0,  0,  1,  1;
   0,  0,  0,  0, -1, -1,  1;
   0,  0,  0,  0,  0,  0,  1,  1;
   0,  0,  0,  0,  0,  0, -1, -1,  1; ...
where P^-1 shifts columns left and up one place:
   1;
  -1,  1;
   0,  1,  1;
   0, -1, -1,  1;
   0,  0,  0,  1,  1;
   0,  0,  0, -1, -1,  1; ...

Crossrefs

Cf. A111941 (matrix log), A111942, A110503 (variant).

Programs

  • PARI
    {P(n,k,q=-1) = local(A=Mat(1),B); if(n

Formula

The g.f. of column k of matrix power P^m (ignoring leading zeros) is:
cos(m*arccos(1-x^2/2)) + (-1)^k * sin(m*arccos(1-x^2/2)) * (1-x/2) / sqrt(1-x^2/4).
Showing 1-6 of 6 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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