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.

A344071 Number of 2n-step self-avoiding cycles on the Laves graph.

Original entry on oeis.org

1, 1, 0, 0, 0, 10, 0, 14, 112, 282, 600, 2618, 9400, 27378, 93828, 332070, 1127840, 3818438, 13369560, 46776898, 163073440, 572984748, 2026468708, 7176533646
Offset: 0

Views

Author

Sean A. Irvine, May 09 2021

Keywords

Crossrefs

Extensions

Name clarified by Andrey Zabolotskiy, Jun 03 2021

A344040 Number of n-step self-avoiding walks on the Laves graph with no non-contiguous adjacencies.

Original entry on oeis.org

1, 3, 6, 12, 24, 48, 96, 192, 384, 738, 1446, 2832, 5544, 10818, 21138, 40980, 79848, 155406, 302526, 587232, 1141620, 2214102, 4300410, 8340876, 16188108, 31368204, 60840540, 117858042, 228471396, 442435860, 857273136, 1659450072, 3214094028, 6220079160
Offset: 0

Views

Author

Sean A. Irvine, May 07 2021

Keywords

Crossrefs

Extensions

Name clarified by Andrey Zabolotskiy, Jun 03 2021

A046944 Number of self-avoiding walks of length n on the Laves graph.

Original entry on oeis.org

1, 3, 6, 12, 24, 48, 96, 192, 384, 768, 1506, 2982, 5904, 11688, 23094, 45678, 90000, 177660, 349938, 690192, 1359288, 2678808, 5271558, 10381926, 20419224, 40191084, 79025262, 155469228, 305582724, 600935844, 1180783482, 2321203446, 4559743116, 8960747616
Offset: 0

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Author

Keywords

Comments

The Leu reference gives 31 terms, but apparently is incorrect for a(25) onward.
Previous name: Number of self-avoiding walks of length n on hydrogen peroxide lattice.

Crossrefs

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 25 2010
a(25) onward corrected by Sean A. Irvine, May 06 2021
Name clarified by Andrey Zabolotskiy, Jun 03 2021

A038621 Growth function of an infinite cubic graph (number of nodes at distance <=n from fixed node).

Original entry on oeis.org

1, 4, 10, 22, 46, 81, 129, 198, 284, 392, 530, 691, 883, 1114, 1374, 1674, 2022, 2405, 2837, 3326, 3856, 4444, 5098, 5799, 6567, 7410, 8306, 9278, 10334, 11449, 12649, 13942, 15300, 16752, 18306, 19931, 21659, 23498, 25414, 27442, 29590, 31821, 34173, 36654
Offset: 0

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Author

Keywords

Comments

Partial sums of A038620.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(x + 1) (2 x^8 - 4 x^7 + 3 x^6 - x^5 + 6 x^4 + 2 x^3 + 2 x^2 + x + 1)/((x - 1)^4 (x^2 + x + 1)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Oct 22 2013 *)
    LinearRecurrence[{2,-1,2,-4,2,-1,2,-1},{1,4,10,22,46,81,129,198,284,392},50] (* Harvey P. Dale, Sep 03 2016 *)

Formula

a(0)=1, a(1)=4; for n>=2: if n == 0 (mod 3), a(n) = (4*n^3 + 6*n^2 + 15*n - 9)/9; if n == 1 (mod 3), a(n) = (4*n^3 + 6*n^2 + 18*n - 10)/9; if n == 2 (mod 3), a(n) = (4*n^3 + 6*n^2 + 15*n + 4)/9.
G.f.: (x+1)*(2*x^8-4*x^7+3*x^6-x^5+6*x^4+2*x^3+2*x^2+x+1) / ((x-1)^4*(x^2+x+1)^2). - Colin Barker, May 10 2013

Extensions

More terms from Colin Barker, May 10 2013

A290705 Theta series of triamond.

Original entry on oeis.org

1, 3, 0, 6, 0, 6, 8, 12, 6, 9, 0, 6, 0, 18, 0, 12, 12, 12, 0, 18, 0, 12, 24, 12, 8, 21, 0, 24, 0, 6, 0, 24, 6, 24, 0, 12, 0, 30, 24, 12, 24, 12, 0, 30, 0, 30, 0, 24, 24, 27, 0, 12, 0, 18, 32, 36, 0, 24, 0, 18, 0, 30, 0, 36, 12, 12, 0, 42, 0, 24, 48, 12, 30
Offset: 0

Views

Author

Andrey Zabolotskiy, Aug 09 2017

Keywords

Comments

Theta series with respect to a node of a lattice known as triamond, Laves graph [embedded in space], K_4 lattice, (10,3)-a, or srs net. This lattice possesses the "strong isotropic" property; the only other lattice that has this property in 3 dimensions is the diamond lattice. Unlike diamond, triamond is chiral.
A004013 and 3*A045828, interleaved.

Crossrefs

See A038620 for coordination sequence.

Programs

  • Mathematica
    (* count lattice sites straightforwardly *)
    cell = Join @@ ({#, # + {1, 1, 1}/2} & /@ {{0, 0, 0}, {1/4, 0, 1/4}, {-1/4, -1/4, 0}, {0, 1/4, -1/4}}); (* lattice sites in a conventional bcc unit cell *)
    n = 10;
    s = O[q]^(n^2 + 1) + Sum[q^(8 Norm[a + {i, j, k}]^2), {i, -n-1, n+1}, {j, -n-1,  n+1}, {k, -n-1, n+1}, {a, cell}];
    CoefficientList[Normal[s], q] &
    (* or use the generation function *)
    a[n_] := SeriesCoefficient[ EllipticTheta[3, 0, x^8]^3 + EllipticTheta[ 2, 0, x^8]^3 + 3/4 EllipticTheta[3, 0, x^2] EllipticTheta[2, 0, x^2]^2, {x, 0, n}];

A344126 Coordination sequence for the hypertriangular lattice.

Original entry on oeis.org

1, 6, 24, 48, 86, 138, 192, 260, 348, 432, 530, 654, 768, 896, 1056, 1200, 1358, 1554, 1728, 1916, 2148, 2352, 2570, 2838, 3072, 3320, 3624, 3888, 4166, 4506, 4800, 5108, 5484, 5808, 6146, 6558, 6912, 7280, 7728, 8112, 8510, 8994, 9408, 9836, 10356, 10800
Offset: 0

Views

Author

Sean A. Irvine, May 09 2021

Keywords

Crossrefs

Formula

G.f.: (1+5*x+18*x^2+22*x^3+28*x^4+16*x^5+7*x^6-3*x^7+2*x^8) / ((x^2+x+1)^2 * (1-x)^3).

A126591 Coordination sequence of a point in the sphere packing 4/3/c27 of Fischer, or the lcv-a net.

Original entry on oeis.org

1, 4, 6, 11, 12, 22, 24, 44, 48, 88, 91, 128, 111, 182, 167, 254, 223, 296, 259, 392, 351, 516, 420, 536, 470, 682, 598, 850, 682, 872, 746, 1044, 908, 1264, 1007, 1280, 1087, 1502, 1283, 1750, 1395
Offset: 0

Views

Author

Wilfrid E. Klee (wiwi.klee(AT)inka.de), Mar 23 2007, Apr 03 2007

Keywords

Comments

Space group of the packing is I4(1)32. The terms are computed using the TOPOLAN program.

Crossrefs

Cf. A038620.

Extensions

Name edited by Andrey Zabolotskiy, Oct 05 2017
Showing 1-7 of 7 results.