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A139813 A polynomial triangle based on cross binomial Hodge number matrices/ Hodge diamonds that represent Calabi-Yau type binomials and their monomials. 1
1, 2, 2, 2, 2, 2, 2, 6, 6, 2, 2, 8, 6, 8, 2, 2, 10, 20, 20, 10, 2, 2, 12, 30, 20, 30, 12, 2, 2, 14, 42, 70, 70, 42, 14, 2, 2, 16, 56, 112, 70, 112, 56, 16, 2, 2, 18, 72, 168, 252, 252, 168, 72, 18, 2, 2, 20, 90, 240, 420, 252, 420, 240, 90, 20, 2 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The matrices M(n X n): crossed Pascal matrices:

{{1}}

---

{{1,1},

{1,1}}

---

{{1,0,1},

{0,2,0},

{1,0,1}}

---

{{1,0,0,1},

{0,3,3,0}.

{0,3,3,0},

{1,0,0,1}}

---

{{1,0,0,0,1},

{0,4,0,4.0},

{0,0,6,0,0},

{0,4,0,4.0},

{1,0,0,0,1}}

---

{{1,0,0,0,01},

{0,5,0,0,5.0},

{0,0,10,10,0,0},

{0,0,10,10,0,0},

{0,5,0,0,5.0},

{1,0,0,0,01}}

Row sums: {1, 4, 6, 16, 26, 64, 108, 256, 442, 1024, 1796, ...}.

Fourier-like visualization of the polynomials:

s = Table[ParametricPlot3D[{g[[n]] /. x -> Cos[t], g[[

n]] /. x -> Sin[t], n3}, {t, -Pi, Pi}], {n, 1, 10}];

Show[s, PlotRange -> All]

These are Calabi-Yau type n-fold manifolds as Hodge monomial polynomials.

The K3 Hodge number matrix/ diamond is ( 2+20*x+23*x^2 ): M is

{{1,0,1},

{0,20,0},

{1,0,1}}

That matrix is this M[3] matrix 3X3 with the central 2 multiplied by a constant 10.

This kind of polynomial has been a staple of Calabi-Yau Algebraic Geometry of varieties since the early 90's.

The highest n-fold Hodge diamond matrices that I found in the literature that gave me this idea was by Rolf Schimrigk (see links).

REFERENCES

Christian Meyer, Modular Calabi-Yau threefolds, 2005.

LINKS

Table of n, a(n) for n=1..66.

Rolf Schimmrigk Mirror Symmetry and String Vacua from a Special Class of Fano Varieties, arXiv:hep-th/9405087

FORMULA

Matrices: T(n,m,d)= If[n - m == 0, Binomial[d, n], If[d - n - m == 0, Binomial[d, m], 0]]; T(n,m,d)->Matrix M(d]); Polynomials in two variables: p(x,y,d)=Sum[Sum[M[d][[k, m]]*x^(k - 1)*y^(m - 1), {m, 1, d + 1}], {k, 1, d + 1}]; Sequence is: a(n,m)_out=Coefficients(p(x,1,d)).

EXAMPLE

{1},

{2, 2},

{2, 2, 2},

{2, 6, 6, 2},

{2, 8, 6, 8, 2},

{2, 10, 20, 20, 10, 2},

{2, 12, 30, 20, 30, 12, 2},

{2, 14, 42, 70, 70, 42, 14, 2},

{2, 16, 56, 112, 70, 112, 56, 16, 2},

{2, 18, 72, 168, 252, 252, 168, 72, 18, 2},

{2, 20, 90, 240, 420, 252, 420, 240, 90, 20, 2}

MATHEMATICA

Clear[T, M, p, a, g] T[n_, m_, d_] := If[n - m == 0, Binomial[d, n], If[d - n - m == 0, Binomial[d, m], 0]]; M[d_] := Table[T[n, m, d], {n, 0, d}, {m, 0, d}]; p[x_, y_, d_] := Sum[Sum[M[d][[k, m]]*x^(k - 1)*y^(m - 1), {m, 1, d + 1}], {k, 1, d + 1}]; g = Table[ExpandAll[p[x, 1, d]], {d, 1, 10}]; a = Join[{{1}}, Table[CoefficientList[p[x, 1, w], x], {w, 1, 10}]]; Flatten[a] Join[{1}, Table[Apply[Plus, CoefficientList[p[x, 1, w], x]], {w, 1, 10}]];

CROSSREFS

Sequence in context: A244461 A105255 A140818 * A172009 A299150 A202448

Adjacent sequences:  A139810 A139811 A139812 * A139814 A139815 A139816

KEYWORD

nonn,tabl,uned

AUTHOR

Roger L. Bagula and Gary W. Adamson, May 23 2008

STATUS

approved

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Last modified April 5 13:26 EDT 2020. Contains 333241 sequences. (Running on oeis4.)