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.

A129067 Leading term in row n of triangle in A128894.

Original entry on oeis.org

3, 8, 14, 28, 52, 78, 133, 190, 248, 484
Offset: 1

Views

Author

Roger L. Bagula, May 11 2007

Keywords

Comments

The building exceptional group symmetry sequence in Cartan notation is (Deligne-Landsberg): {A1,A2,G2,D4,F4,E6,E7,E7.5,E8,E9} E9 seems to be closer to an E9.5. For a universe which is E8 symmetry to have evolved, there had to be a metastable (explosive) higher energy/ higher temperature state E9.

References

  • J. M. Landsberg, The sextonions and E_{7 1/2} (with L.Manivel) (Advances in Math 201(2006) p143 - 179) page 22

Crossrefs

Cf. A128894, A109161, A129024, A129025.

Programs

  • Mathematica
    (*A128894*) (*http : // www.math.tamu.edu/~jml /: The sextonions and E_{7 1/2} (with L.Manivel) (Advances in Math 201(2006) p143 - 179) : http : // www.math.tamu.edu/~jml/LMsexpub.pdf : page 22*) a = {-4/3, -1, -2/3, 0, 1, 2, 4, 6, 8, 16}; g[a_, k_] := (3*a + 2*k + 5)*Binomial[k + 2*a + 3, k]* Binomial[k + 5*a/2 + 3, k]*Binomial[k + 3*a + 4, k]/((3*a + 5)*Binomial[k + a/2 + 1, k]*Binomial[k + a + 1, k]) b = Table[g[a[[n]], 1], {n, 1, Length[a]}]

Formula

T(a,n) =(3*a + 2*k + 5)*binomial[k + 2*a + 3, k]*binomial[ k + 5*a/2 + 3, k]*binomial[k + 3*a + 4, k]/((3*a + 5)*binomial[k + a/2 + 1, k]*binomial[k + a + 1, k]) b = Table[Table[g[a[[n]], k], {k, 1, n}], {n, 1, Length[a]}]; k=1 T[n,1]

A129068 A128894[n,k] for k=1 : Coxeter numbers as defined by Bulgadaev for exceptional group sequence using critical exponent solution.

Original entry on oeis.org

2, 3, 3, 6, 9, 12, 18, 24, 30, 50
Offset: 1

Views

Author

Roger L. Bagula, May 11 2007

Keywords

Comments

The building exceptional group symmetry sequence in Cartan notation is ( Deligne-Landsberg): {A1,A2,G2,D4,F4,E6,E7,E7.5,E8,E9} The Coxeter number seem to be related to the total powers in the elliptical invariants for exceptional groups. I have used 2/11 for the F4 critical exponent instead of Bulgadaev's 1/4 because 2/11 fits the linearity of the groups better.

References

  • J. M. Landsberg, The sextonions and E_{7 1/2} (with L.Manivel) (Advances in Math 201(2006) p143 - 179) page 22

Links

Crossrefs

Cf. A128894, A109161, A129024, A129025.

Programs

  • Mathematica
    (*S.A Bulgadaev, arXiv : hep - th/9906091v1 12 Jun 1999*)  b = {2/(1 + 3), 2/(2 + 3), 2/5, 1/4, 2/11, 1/7, 1/10, 1/13, 1/16, 1/26}; hg = Flatten[Table[x /. Solve[2/(2 + x) - b[[n]] == 0, x], {n, 1, Length[b]}]]

Formula

Criticalexponent=k/(k+hg)={2/(1 + 3), 2/(2 + 3), 2/5, 1/4, 2/11, 1/7, 1/10, 1/13, 1/16, 1/26}; hg=Coxeter number=(number of roots)/(rank of group) hg = Flatten[Table[x /. Solve[2/(2 + x) - b[[n]] == 0, x], {n, 1, Length[b]}]]

A133238 Dimensions of certain Lie algebra (see reference for precise definition).

Original entry on oeis.org

1, 52, 1053, 12376, 100776, 627912, 3187041, 13748020, 51949755, 175847880, 542393670, 1544927904, 4107092288, 10278624864, 24388573014, 55188666312, 119696471453, 249869263644, 503865726155, 984563860280, 1869304764600, 3456658569000, 6238533257775
Offset: 0

Views

Author

N. J. A. Sloane, Oct 15 2007

Keywords

Links

Crossrefs

The cases a = -4/3, -1, -2/3, 0, 1, 2, 4, 6, 8 of Th. 7.1 of Landsberg and Manivel give sequences A005408, A000578, A085462, A107942, A133238 (this entry), A133239, A133240, A133241 and A030650 respectively. See also triangle in A128894.

Programs

  • Maple
    b:=binomial; t71:= proc(a,k) ((3*a+2*k+5)/(3*a+5)) * b(k+2*a+3,k)*b(k+5*a/2+3,k)*b(k+3*a+4,k)/(b(k+a/2+1,k)*b(k+a+1,k)); end; [seq(t71(1,k),k=0..30)];
  • Mathematica
    t71[a_, k_] := (3a+2k+5) / (3a+5) Binomial[k+2a+3,k] Binomial[k+5/2a+3,k] Binomial[k+3a+4,k] / (Binomial[k+a/2+1,k] Binomial[k+a+1,k]);
Array[t71[1,#]&,30,0] (* Paolo Xausa, Jan 11 2024 *)

Formula

Empirical g.f.: (x^8+36*x^7+341*x^6+1208*x^5+1820*x^4+1208*x^3+341*x^2+36*x+1) / (x-1)^16. - Colin Barker, Jul 27 2013
Showing 1-3 of 3 results.

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