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.

User: William Lionheart

William Lionheart's wiki page.

William Lionheart has authored 2 sequences.

A307897 Duplicate of A008651.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 2, 3, 3, 2, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 4, 3, 3, 3, 3, 3, 4, 3, 3, 3, 4
Offset: 0

Author

William Lionheart, May 04 2019

Keywords

Comments

Meyer's generating function h(t,G) generates the sequence of the dimensions of the spaces of G-invariant harmonic polynomials of each degree, where G is a point group on three-dimensional Euclidean space. For G=I, the icosahedral rotation group, the generating function gives rise to this sequence. See Table 1, p. 143.

Programs

  • Mathematica
    CoefficientList[ Series[(1 - t^10)^(-1) (1 - t^6)^(-1) (1 + t^15), {t, 0, 100}], t]
  • PARI
    Vec((1 + x - x^3 - x^4 - x^5 + x^7 + x^8) / ((1 - x)^2*(1 + x)*(1 + x + x^2)*(1 + x + x^2 + x^3 + x^4)) + O(x^60)) \\ Colin Barker, May 04 2019

Formula

G.f.: (1 + t^15) / ( (1 - t^10) * (1 - t^6) ).
a(n) = -a(n-1) + a(n-3) + a(n-4) + a(n-5) + a(n-6) - a(n-8) - a(n-9) for n>8. - Colin Barker, May 04 2019

A325488 Dimensions of space of harmonic polynomials of each degree invariant under the full icosahedral group.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 2, 0, 1, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 3, 0, 2, 0, 2, 0, 3, 0, 2, 0, 3, 0, 3, 0, 2, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 3, 0, 4, 0, 3, 0, 3, 0, 4, 0, 3, 0, 4
Offset: 0

Author

William Lionheart, May 04 2019

Keywords

Comments

Meyer's generating function h(t,G) generates the sequence of the dimensions of the spaces of G-invariant harmonic polynomials of each degree, where G is a point group on three-dimensional Euclidean space. For G=I_h, the full icosahedral group including inversions, the generating function is 1/((1 - t^10)*(1 - t^6)).

Crossrefs

Cf. A008651 for the icosahedral rotation group which is derived from this sequence using Theorem 8 of Meyer, h(t,I)=(1+t^15)*h(t,I_h) as I_h has 15 symmetry planes.

Programs

  • Mathematica
    CoefficientList[Series[(1 - t^10)^(-1) (1 - t^6)^(-1) , {t, 0, 100}],
      t]
  • PARI
    Vec(1 / ((1 - x)^2*(1 + x)^2*(1 - x + x^2)*(1 + x + x^2)*(1 - x + x^2 - x^3 + x^4)*(1 + x + x^2 + x^3 + x^4)) + O(x^100)) \\ Colin Barker, Jun 26 2019

Formula

G.f.: 1/((1 - t^10)*(1 - t^6)).
a(n) = a(n-6) + a(n-10) - a(n-16) for n>15. - Colin Barker, Jun 26 2019