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 1-10 of 11 results. Next

A019441 Coefficients in generating function for radius of gyration of the sequence A066158.

Original entry on oeis.org

1, 2, 28, 244, 1680, 10214, 57476, 305476, 1553632, 7641218, 36608932, 171666468, 790650724, 3586822020, 16062938368, 71135451440, 311964025352, 1356392904818, 5852609697844, 25081266854732
Offset: 1

Views

Author

N. J. A. Sloane, Nov 05 2008

Keywords

Crossrefs

A192074 a(n) = A066158(n)-2 with a(0)=1.

Original entry on oeis.org

0, 0, 4, 16, 53, 172, 568, 1906, 6471, 22200, 76884, 268350, 942649, 3329606, 11817580, 42120338, 150682448, 540832272, 1946892840, 7027047846, 25424079337, 92185846606, 334925007126, 1219054432488, 4444545298877, 16229462702150, 59347661054362
Offset: 1

Views

Author

N. J. A. Sloane, Jun 22 2011

Keywords

Crossrefs

A118356 Number of clusters with n vertices, n-1 edges and zero contacts on the simple cubic lattice.

Original entry on oeis.org

1, 3, 15, 83, 486, 2967, 18748, 121725, 807381, 5447203, 37264974, 257896500, 1802312605, 12701190885, 90157130289, 644022007040, 4626159163233
Offset: 1

Views

Author

R. J. Mathar, May 14 2006

Keywords

Comments

a(n)<=A001931(n) due to the "no-contact" restriction.
An alternative wording for a(n) is the number of n-cell fixed tree-like polycubes in 3 dimensions. - Gill Barequet, May 25 2011

References

  • G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

Crossrefs

Cf. A066158 (fixed tree-like polyominoes), A191094, A191095, A191096, A191097, A191098 (fixed tree-like polycubes in 4, 5, 6, 7, and 8 dimensions, resp.).

Extensions

a(1)=1 added by Gill Barequet, May 25 2011

A191094 Number of n-cell fixed tree-like polycubes in 4 dimensions.

Original entry on oeis.org

1, 4, 28, 228, 2018, 18892, 184400, 1857856, 19189675, 202214452
Offset: 1

Views

Author

Gill Barequet, May 25 2011

Keywords

References

  • G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

Crossrefs

Cf. A066158 (fixed tree-like polyominoes), A118356, A191095, A191096, A191097, A191098 (fixed tree-like polycubes in 3, 5, 6, 7, and 8 dimensions, resp.).

A061157 Numbers k such that k*2^m-1 is prime for exactly one exponent m in the range 0<=m<=k.

Original entry on oeis.org

11, 22, 37, 74, 109, 151, 247, 253, 337, 382, 403, 506, 509, 547, 674, 739, 764, 779, 806, 1325, 1478, 1528, 1558, 1589, 1597, 1612, 1871, 1987, 2263, 2279, 2317, 2759, 2797, 3056, 3116, 3194, 3329, 3341, 3719, 3742, 3761, 3821, 4001, 4412, 4526, 4558, 4559, 4603, 4736, 4813
Offset: 1

Views

Author

Patrick De Geest, Apr 15 2001

Keywords

Crossrefs

Cf. A061153, A061154, A061155, A061156. See A066158 for exponents.

Extensions

Offset corrected and more terms from Sean A. Irvine, Jan 24 2023

A191095 Number of n-cell fixed tree-like polycubes in 5 dimensions.

Original entry on oeis.org

1, 5, 45, 485, 5775, 73437, 979335, 13536225, 192393410, 2796392165
Offset: 1

Views

Author

Gill Barequet, May 25 2011

Keywords

References

  • G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

Crossrefs

Cf. A066158 (fixed tree-like polyominoes), A118356, A191094, A191096, A191097, A191098 (fixed tree-like polycubes in 3, 4, 6, 7, and 8 dimensions, resp.).

A191096 Number of n-cell fixed tree-like polycubes in 6 dimensions.

Original entry on oeis.org

1, 6, 66, 886, 13281, 213978, 3630090, 64012932
Offset: 1

Views

Author

Gill Barequet, May 25 2011

Keywords

References

  • G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

Crossrefs

Cf. A066158 (fixed tree-like polyominoes), A118356, A191094, A191095, A191097, A191098 (fixed tree-like polycubes in 3, 4, 5, 7, and 8 dimensions, resp.).

A191097 Number of n-cell fixed tree-like polycubes in 7 dimensions.

Original entry on oeis.org

1, 7, 91, 1463, 26460, 516691, 10654378
Offset: 1

Views

Author

Gill Barequet, May 25 2011

Keywords

References

  • G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

Crossrefs

Cf. A066158 (fixed tree-like polyominoes), A118356, A191094, A191095, A191096, A191098 (fixed tree-like polycubes in 3, 4, 5, 6, and 8 dimensions, resp.).

A191098 Number of n-cell fixed tree-like polycubes in 8 dimensions.

Original entry on oeis.org

1, 8, 120, 2248, 47636, 1088017, 26424957
Offset: 1

Views

Author

Gill Barequet, May 25 2011

Keywords

References

  • G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

Crossrefs

Cf. A066158 (fixed tree-like polyominoes), A118356, A191094, A191095, A191096, A191097 (fixed tree-like polycubes in 3, 4, 5, 6, and 7 dimensions, resp.).

A196593 Number of fixed tree-like convex polyominoes.

Original entry on oeis.org

1, 2, 6, 18, 51, 134, 328, 758, 1677, 3594, 7530, 15530, 31687, 64190, 129420, 260142, 521889, 1045730, 2093806, 4190402, 8384091, 16772022, 33548496, 67102118, 134210101, 268426874, 536861298, 1073731098, 2147471727, 4294954094, 8589920020, 17179853150
Offset: 1

Views

Author

Gill Barequet, Oct 04 2011

Keywords

Comments

In a 1-1 mapping with permutations that avoid the patterns (1423, 4213, 2314, 2431, 2413, <3142,{2},{2}>) (the fourth pattern is bivincular).

Crossrefs

Cf. A001168 (fixed polyominoes), A066158 (fixed tree polyominoes), A067675 (fixed convex polyominoes).

Programs

  • Mathematica
    LinearRecurrence[{6,-14,16,-9,2},{1,2,6,18,51},50] (* Harvey P. Dale, Oct 16 2011 *)

Formula

G.f.: (x*(1-4*x+8*x^2-6*x^3+4*x^4))/((1-x)^4*(1-2*x)).
a(n) = 6*a(n-1) - 14*a(n-2) + 16*a(n-3) - 9*a(n-4) + 2*a(n-5).
a(n) = 2^(n+2) - (n^3-n^2+10*n+4)/2.
Showing 1-10 of 11 results. Next