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 1-5 of 5 results.

A130185 Third column (m=2) of triangle A130182.

Original entry on oeis.org

1, 4, 28, 216, -2592, -449280, -42405120, -4187635200, -470931148800, -61395115622400, -9285015785472000, -1621094541631488000, -324607299684433920000, -74032650725692538880000, -19101781491742463754240000, -5540523747380685884620800000
Offset: 0

Views

Author

Wolfdieter Lang Jun 01 2007

Keywords

Comments

See the M. Bruschi et al. reference and the W. Lang link given in A130182.

Crossrefs

Cf. A130186 (fourth column).

Formula

a(n)= A130185(n+2,2), n>=0.

A130186 Fourth column (m=3) of triangle A130182.

Original entry on oeis.org

1, 20, 508, 17400, 788688, 46032768, 3372731136, 303444195840, 32898989030400, 4229445205094400, 635789661109862400, 110396039984094412800, 21901378996153294848000, 4915686113045739601920000
Offset: 0

Views

Author

Wolfdieter Lang Jun 01 2007

Keywords

Comments

See the M. Bruschi et al. reference and the W. Lang link given in A130182.

Crossrefs

Cf. A130185 (third column).

Formula

a(n)= A130186(n+3,3), n>=0.

A130183 Row sums of triangle A130182.

Original entry on oeis.org

1, -1, -1, -7, -95, -2105, -68945, -3126895, -187481215, -14354383825, -1366150472225, -158177224078775, -21890843392951775, -3568350888585380425, -676628627780999760625, -147662618352313843681375, -36745377178714846268837375, -10342398978039119692295758625
Offset: 0

Views

Author

Wolfdieter Lang Jun 01 2007

Keywords

Comments

See the Bruschi et al. reference given in A130182.

Crossrefs

Cf. A130184 (unsigned row sums).

Formula

a(n)=sum(A130182(n,m),m=0..n),n>=0.

A130184 Row sums of unsigned triangle A130182.

Original entry on oeis.org

1, 3, 3, 17, 193, 3655, 109039, 5029265, 303754625, 23283529775, 2209349713375, 254313174846025, 34919610311752225, 5639344047544155575, 1058308036809581999375, 228404316795631157278625
Offset: 0

Views

Author

Wolfdieter Lang Jun 01 2007

Keywords

Comments

See the M. Bruschi et al. reference given in A130182.

Crossrefs

Cf. A130183 (row sums).

Formula

a(n)=sum(|A130182(n,m)|,m=0..n),n>=0.

A130559 Coefficients of the v=n member of a family of certain orthogonal polynomials with Diophantine properties.

Original entry on oeis.org

1, -2, 1, 12, -8, 1, -144, 108, -20, 1, 2880, -2304, 508, -40, 1, -86400, 72000, -17544, 1708, -70, 1, 3628800, -3110400, 808848, -89280, 4648, -112, 1, -203212800, 177811200, -48405888, 5808528, -349568, 10920, -168, 1, 14631321600, -13005619200, 3663035136, -466619904
Offset: 0

Views

Author

Wolfdieter Lang, Jul 13 2007

Keywords

Comments

For v>=1 the orthogonal polynomials pt(n,v,x) have only integer zeros k*(k+1), k=1..n These integer zeros are from 2*A000217.
Coefficients of pt(n,v=n,x) (in the quoted Bruschi et al. paper {\tilde p}^{(\nu)}_n(x) of eqs. (20) and (24a),(24b)) in increasing powers of x.
The v-family pt(n,v,x) consists of characteristic polynomials of the tridiagonal M x M matrix Vt=Vt(M,v) with entries Vt_{m,n} given by 2*m*(v+1-m) if n=m, m=1,...,M; -m*(v+1-m) if n=m-1, m=2,...,M; -m*(v+1-m) if n=m+1, m=1..M-1 and 0 else. pt(n,v,x):=det(x*I_n-Vt(n,v) with the n dimensional unit matrix I_n.
pt(n,v=n,x) has, for every n>=1, the n integer zeros 2,6,12,...,n*(n+1). pt(2,2,x) has therefore only the integer zeros 2 and 6. 12= 2*6 = det(Vt(2,2))=16-4.
This triangle coincides with triangle A129467 without row n=0 and column m=0, taking as offset again [0,0].
Column sequences give for m=0..2: A010790(n-1)*(-1)^(n-1), A084915(n+1)*(-1)^n, A130033.

Examples

			n=2: [12,-8,1] stands for pt(2,2,x) = 12-8*x+x^2 = (x-2)*(x-6) with the integer zeros 2*1 and 2*3.
Triangle begins:
  [1];
  [-2,1];
  [12,-8,1];
  [-144,108,-20,1];
  [2880,-2304,508,-40,1];
  ...
		

Crossrefs

Row sums give A130031(n+1), n>=0. Unsigned row sums give A130032(n+1), n>=1.
Cf. A130182 (v=1 member).

Formula

a(n,m) = [x^m]pt(n,n,x), n>=0, with the three term recurrence for orthogonal polynomial systems of the form pt(n,v,x) = (x + 2*n*(n-1-v))*pt(n-1,v,x) - (n-1)*n*(n-1-v)*(n-2-v)*pt(n-2,v,x), n>=1; pt(-1,v,x) = 0 and pt(0,v,x) = 1. Start with v = n.
Showing 1-5 of 5 results.