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 1-7 of 7 results.

A288455 Chebyshev coefficients of density of states of BCC lattice.

Original entry on oeis.org

1, -48, 1728, -79872, 4058112, -216956928, 11977752576, -676117610496, 38792847949824, -2253773963526144, 132241430641901568, -7821943674035503104, 465750331610495975424, -27888626411947306254336, 1677958399935741979262976, -101375476324084742212288512, 6146869366762959307806867456
Offset: 0

Views

Author

Yen-Lee Loh, Jun 16 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,2,4,6,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the body-centered cubic lattice (z=8), g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k.
For the bcc lattice (z=8), the even Chebyshev coefficients can be expressed in closed form in terms of the hypergeometric function pFq, as z^{2N} g_{2N} = (1 + delta_N) * 2^(2N-1) Binomial(2N,N)^3 * 4F3 (-N, -N, -N, -N; 1-2N, 1/2-N, 1/2-N; 1).

Crossrefs

Related to numbers of walks returning to origin, W_n, on BCC lattice (A002897).

Programs

  • Mathematica
    zng[n_] :=
      If[OddQ[n], 0,
      (1 + KroneckerDelta[m]) 2^(2 m - 1) *
      Binomial[2m,m]^3 HypergeometricPFQ[{-m,-m,-m,-m}, {1-2m, 1/2-m, 1/2-m}, 1] /. m -> n/2];
    Table[zng[n], {n,0,50}]
    Wchain[n_] := If[OddQ[n], 0, Binomial[n, n/2]];
    Wbcc[n_] := Wchain[n]^3;
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*8^(n-k)*Wbcc[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]

A288456 Chebyshev coefficients of density of states of honeycomb lattice.

Original entry on oeis.org

1, -3, -15, 141, -1503, 9117, -46959, 2349, 1947969, -26479299, 166125105, -476958771, -7411008159, 122517898461, -1220344831791, 7016585864301, -14334148360575, -334610402172291, 4919241139007601, -42532841711020275, 172482611175249057, 717799148664446493, -24646866746992333551
Offset: 0

Views

Author

Yen-Lee Loh, Jun 16 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,2,4,6,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the honeycomb lattice (z=3), g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k.
The author was unable to obtain a closed form for z^n g_n.

Crossrefs

Related to numbers of walks returning to origin, W_n, on honeycomb lattice (A002893).

Programs

  • Mathematica
    Whon[n_] := If[OddQ[n], 0,
       Sum[Binomial[n/2, j]^2 Binomial[2 j, j], {j, 0, n/2}]];
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*3^(n - k)*Whon[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]

A288457 Chebyshev coefficients of density of states of diamond lattice.

Original entry on oeis.org

1, -8, -32, 1024, -12800, 90112, -131072, -2097152, -78774272, 3080716288, -49736056832, 407753457664, -222801428480, -19645180411904, -494299196162048, 22797274090307584, -393216908922454016, 3294704322255781888, 1334801068806111232, -228652837223366918144, -4282607861714030428160, 222230748909257887842304
Offset: 0

Views

Author

Yen-Lee Loh, Jun 16 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,2,4,6,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the diamond lattice (z=4), g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k.
The author was unable to obtain a closed form for z^n g_n.

Crossrefs

Related to numbers of walks returning to origin, W_n, on diamond lattice (A002895).

Programs

  • Mathematica
    Wdia[n_] := If[OddQ[n], 0,
       Sum[Binomial[n/2,j]^2 Binomial[2j,j] Binomial[n-2j, n/2-j], {j, 0, n/2}]];
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*4^(n-k)*Wdia[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]

A288458 Chebyshev coefficients of density of states of cubic lattice.

Original entry on oeis.org

1, -24, 288, -2688, -32256, 2820096, -95035392, 1972076544, -9841803264, -1288894414848, 70351960670208, -2164060518875136, 36664809432809472, 365875642245316608, -55960058736918134784, 2436570173137823465472, -64272155689216515244032, 664295705652718630600704, 35692460661517822602510336
Offset: 0

Views

Author

Yen-Lee Loh, Jun 16 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,2,4,6,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the simple cubic lattice (z=6), g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k.
The author was unable to obtain a closed form for z^n g_n.

Crossrefs

Related to numbers of walks returning to origin, W_n, on cubic lattice (A002896).

Programs

  • Mathematica
    Whon[n_] := If[OddQ[n], 0,
       Sum[Binomial[n/2,j]^2 Binomial[2j,j], {j, 0, n/2}]];
    Wcub[n_] := Binomial[n, n/2] Whon[n];
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*6^(n-k)*Wcub[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]

A288459 Chebyshev coefficients of density of states of 4D hypercubic lattice.

Original entry on oeis.org

1, -48, 1344, -24576, 218112, -688128, 926416896, -95932121088, 5186228846592, -154060166529024, 1455620351852544, -29436202608230400, 17834604768232734720, -1968810407797802926080, 114581075578951670169600, -3629224301781687956668416, 33517817437575659447648256, -1040884075746436707891806208
Offset: 0

Views

Author

Yen-Lee Loh, Jun 16 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,2,4,6,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the four-dimensional hypercubic lattice (z=8), g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k.
The author was unable to obtain a closed form for z^n g_n.

Crossrefs

Related to numbers of walks returning to origin, W_n, on hypercubic lattice (A039699).

Programs

  • Mathematica
    Wdia[n_] := If[OddQ[n], 0,
       Sum[Binomial[n/2,j]^2 Binomial[2j,j] Binomial[n-2j, n/2-j], {j, 0, n/2}]];
    Whcub[n_] := Binomial[n, n/2] Wdia[n];
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*8^(n-k)*Whcub[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]

A288460 Chebyshev coefficients of density of states of triangular lattice.

Original entry on oeis.org

1, 0, -24, 48, 288, -2880, 3072, 64512, -400896, -245760, 12496896, -50688000, -159547392, 2133540864, -4964253696, -42047373312, 313193005056, -179042254848, -8158768005120, 36487616790528, 65397155954688, -1204277276049408, 2427936640598016, 19127143199932416, -107713462133587968, -223101299070074880
Offset: 0

Views

Author

Yen-Lee Loh, Jun 16 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,1,2,3,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the triangular lattice, g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta. The coordination number is z=6. Note that the triangular lattice is sometimes called the hexagonal lattice.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k.
The author was unable to obtain a closed form for z^n g_n.

Crossrefs

Related to numbers of walks returning to origin, W_n, on triangular lattice (A002898).

Programs

  • Mathematica
    Whon[n_] := If[OddQ[n], 0, Sum[Binomial[n/2,j]^2 Binomial[2j,j], {j, 0, n/2}]];
    Wtri[n_] := Sum[Binomial[n,j] (-3)^(n-j) Whon[2j], {j, 0, n}];
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*6^(n - k)*Wtri[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]

A288461 Chebyshev coefficients of density of states of FCC lattice.

Original entry on oeis.org

1, 0, -120, 192, 11232, -69120, -887808, 11870208, 34721280, -1458585600, 4612792320, 124992552960, -1294622392320, -3918630223872, 170411025235968, -1023380614545408, -11537631123996672, 248923798395420672, -709263007722504192, -30740965743050883072, 367936297318798589952, 1683415347595793399808
Offset: 0

Views

Author

Yen-Lee Loh, Jun 19 2017

Keywords

Comments

This is the sequence of integers z^n g_n for n=0,1,2,3,... where g_n are the coefficients in the Chebyshev polynomial expansion of the density of states of the face-centered cubic lattice (z=12), g(w) = 1 / (Pi*sqrt(1-w^2)) * Sum_{n>=0} (2-delta_n) g_n T_n(w). Here |w| <= 1 and delta is the Kronecker delta. The coordination number is z=6. Note that the triangular lattice is sometimes called the hexagonal lattice.
The Chebyshev coefficients, g_n, are related to the number of walks on the lattice that return to the origin, W_n, as g_n = Sum_{k=0..n} a_{nk} z^{-k} W_k, where z is the coordination number of the lattice and a_{nk} are the coefficients of Chebyshev polynomials such that T_n(x) = Sum_{k=0..n} a_{nk} x^k. The author was unable to obtain a closed form for z^n g_n.

Crossrefs

Related to numbers of walks returning to origin, W_n, on FCC lattice (A002899).

Programs

  • Mathematica
    Wdia[n_] := If[OddQ[n], 0,
       Sum[Binomial[n/2,j]^2 Binomial[2j,j] Binomial[n-2j, n/2-j], {j, 0, n/2}]];
    Wfcc[n_] := Sum[Binomial[n, j] (-4)^(n-j) Wdia[2 j], {j, 0, n}];
    ank[n_, k_] := SeriesCoefficient[ChebyshevT[n, x], {x, 0, k}];
    zng[n_] := Sum[ank[n, k]*12^(n-k)*Wfcc[k], {k, 0, n}];
    Table[zng[n], {n,0,50}]
Showing 1-7 of 7 results.