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.

Previous Showing 21-27 of 27 results.

A068265 1/15 the number of colorings of an n X n square array with 15 colors.

Original entry on oeis.org

1, 2562, 1121513134, 83883341208384732, 1071996076636962150571633386, 2340759471154169773945494478241264553960, 873306114650864371018759651512626175923988398193371716, 55670142239312854542084127479622099015674204276236803402441613218850844
Offset: 1

Views

Author

R. H. Hardin, Feb 24 2002

Keywords

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

Extensions

a(5)-a(8) from Alois P. Heinz, Apr 27 2012

A068266 1/16 the number of colorings of an n X n square array with 16 colors.

Original entry on oeis.org

1, 3165, 1982119455, 245622604880564955, 6022672393066051875922651155, 29220829891835424567142114269163936868895, 28052931461360411640129365206060753190589761972840149815, 5329007775881376959796836954274567596610268811025721999774999394622215355
Offset: 1

Views

Author

R. H. Hardin, Feb 24 2002

Keywords

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

Extensions

a(5)-a(8) from Alois P. Heinz, Apr 27 2012

A068267 1/17 the number of colorings of an n X n square array with 17 colors.

Original entry on oeis.org

1, 3856, 3373402576, 669566077899139456, 30151771791510037597255660816, 308053647651282803104693654675496996201056, 714058835879284684324470416584413995932326192121670240896, 375522326791659350740130359662485880296223549591107434149113597657567050816
Offset: 1

Views

Author

R. H. Hardin, Feb 24 2002

Keywords

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

Extensions

a(5)-a(8) from Alois P. Heinz, Apr 27 2012

A068268 1/18 the number of colorings of an n X n square array with 18 colors.

Original entry on oeis.org

1, 4641, 5554571857, 1714419367669298289, 136461767759964622690609683537, 2801124263786734144622842493797034683405617, 14827953377838619886793709359009173477911476430325930106481, 20242190237452646688395985657256161903754274932459524235140863308223305109841
Offset: 1

Views

Author

R. H. Hardin, Feb 24 2002

Keywords

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

Extensions

a(5)-a(8) from Alois P. Heinz, Apr 27 2012

A068269 1/19 the number of colorings of an n X n square array with 19 colors.

Original entry on oeis.org

1, 5526, 8882874018, 4153630571837864748, 564981170863476314096512687566, 22354853275061169487985050625489956484533056, 257300965334378745090532920060644632998190650709754736514068, 861475141050998806961235302195978945049151803599433480523424276423626596675468
Offset: 1

Views

Author

R. H. Hardin, Feb 24 2002

Keywords

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

Extensions

a(5)-a(8) from Alois P. Heinz, Apr 27 2012

A068270 1/20 the number of colorings of an n X n square array with 20 colors.

Original entry on oeis.org

1, 6517, 13841287219, 9580458187250990407, 2161111220298293067819628379911, 158872597397775739573835110149847235229271675, 3806290340846629510463844992746098005507806101928649895595171, 29719114772241665792629546781476756531800106771541628945462624575440369135473679
Offset: 1

Views

Author

R. H. Hardin, Feb 24 2002

Keywords

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A182368, A182406.

Extensions

a(5)-a(8) from Alois P. Heinz, Apr 27 2012

A182517 Chromatic invariant of the square grid graph G_(n,n).

Original entry on oeis.org

1, 1, 3, 72, 11423, 11187798, 65460885384, 2247082682913972, 447548280314975144427, 513427482871084962707467332
Offset: 1

Views

Author

Alois P. Heinz, May 03 2012

Keywords

Comments

The square grid graph G_(n,n) has n^2 = A000290(n) vertices and 2*n*(n-1) = A046092(n-1) edges. The chromatic invariant equals the absolute value of the first derivative of the chromatic polynomial evaluated at 1.

Links

Crossrefs

Cf. A000290, A046092, A182368 (chromatic polynomial).

Programs

  • Mathematica
    Abs[Table[Derivative[1][ChromaticPolynomial[GridGraph[{n, n}]]][1], {n, 7}]] (* Eric W. Weisstein, May 01 2017 *)

Formula

a(n) = |(d/dq P(n,q)){q=1}| with P(n,q) = Sum{k=0..n^2} A182368(n,k) * q^(n^2-k).

Extensions

a(10) from Andrew Howroyd, Apr 23 2018
Previous Showing 21-27 of 27 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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