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 1-5 of 5 results.

A212269 Number of ways to place k non-attacking kings on an n X n cylindrical chessboard, summed over all k >= 0.

Original entry on oeis.org

2, 5, 19, 205, 3011, 92875, 4763459, 459630701, 78223965193, 24270274906085, 13497818986883771, 13571363009654254429, 24562890586806439035377, 80199120146273882569630015, 471874707649862024071657639861, 5005895207027974222377733802848093
Offset: 1

Views

Author

Vaclav Kotesovec, May 12 2012

Keywords

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, p. 343.

Crossrefs

Formula

Limit n ->infinity (a(n))^(1/n^2) = 1.342643951124... (see A247413).

A194651 Number of ways to place 3 nonattacking kings on an n X n cylindrical chessboard.

Original entry on oeis.org

0, 0, 0, 88, 785, 3528, 11151, 28560, 63513, 127520, 236863, 413736, 687505, 1096088, 1687455, 2521248, 3670521, 5223600, 7286063, 9982840, 13460433, 17889256, 23466095, 30416688, 38998425, 49503168, 62260191, 77639240, 96053713, 117963960, 143880703
Offset: 1

Views

Author

Vaclav Kotesovec, Aug 31 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[-x^3*(15*x^6 - 89*x^5 + 196*x^4 - 140*x^3 - 119*x^2 + 169*x + 88)/(x - 1)^7, {x, 0, 30}], x] (* Wesley Ivan Hurt, Dec 27 2023 *)

Formula

a(n) = 1/6*n*(n^5 - 27*n^3 + 18*n^2 + 194*n - 228), n>=4.
G.f.: -x^4*(15*x^6 - 89*x^5 + 196*x^4 - 140*x^3 - 119*x^2 + 169*x + 88)/(x-1)^7.

A194652 Number of ways to place 4 nonattacking kings on an n X n cylindrical chessboard.

Original entry on oeis.org

0, 0, 0, 32, 1205, 13260, 74494, 291708, 908973, 2416410, 5711530, 12327414, 24743693, 46797968, 84216990, 145288600, 241697109, 389546478, 610597338, 933745570, 1396771845, 2048393204, 2950649438, 4181658708, 5838778525, 8042209890, 10939084074, 14708073198
Offset: 1

Views

Author

Vaclav Kotesovec, Aug 31 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[x^3*(54*x^9 - 384*x^8 + 1052*x^7 - 1263*x^6 + 657*x^5 - 1434*x^4 + 4154*x^3 - 3567*x^2 - 917*x - 32)/(x - 1)^9, {x, 0, 30}], x] (* Wesley Ivan Hurt, Dec 27 2023 *)

Formula

a(n) = 1/24*n*(n^7 - 54*n^5 + 36*n^4 + 1019*n^3 - 1236*n^2 - 6690*n + 10884), n>=5.
G.f.: x^4*(54*x^9 - 384*x^8 + 1052*x^7 - 1263*x^6 + 657*x^5 - 1434*x^4 + 4154*x^3 - 3567*x^2 - 917*x - 32)/(x-1)^9.

A194653 Number of ways to place 5 nonattacking kings on an n X n cylindrical chessboard.

Original entry on oeis.org

0, 0, 0, 0, 655, 26952, 309869, 1998752, 9124848, 33065040, 101473009, 274593648, 673080928, 1522931256, 3224953725, 6458355776, 12330557912, 22588294464, 39908439249, 68290845520, 113579839128, 184145882536, 291764365485, 452734505952, 689287992800
Offset: 1

Views

Author

Vaclav Kotesovec, Aug 31 2011

Keywords

Crossrefs

Formula

a(n) = 1/120*n*(n^9 - 90*n^7 + 60*n^6 + 3155*n^5 - 3900*n^4 - 50910*n^3 + 86580*n^2 + 318864*n - 656160), n>=6.
G.f.: -x^5*(185*x^11 - 1635*x^10 + 6336*x^9 - 15496*x^8 + 32185*x^7 - 62315*x^6 + 86237*x^5 - 49559*x^4 - 35522*x^3 + 49422*x^2 + 19747*x + 655)/(x-1)^11.

A194654 Number of ways to place 6 nonattacking kings on an n X n cylindrical chessboard.

Original entry on oeis.org

0, 0, 0, 0, 125, 28930, 809368, 9414152, 66305781, 338374560, 1378426060, 4751038284, 14388638901, 39296604844, 98605016040, 230507248912, 507379370525, 1060395103800, 2118303772332, 4066797540820, 7537144196589, 13535598398916, 23628635128024, 40203393674520
Offset: 1

Views

Author

Vaclav Kotesovec, Aug 31 2011

Keywords

Crossrefs

Formula

a(n) = 1/720*n*(n^11 - 135*n^9 + 90*n^8 + 7525*n^7 - 9420*n^6 - 216045*n^5 + 378090*n^4 + 3192694*n^3 - 6899520*n^2 - 19450080*n + 48327120), n>=7.
G.f.: x^5*(622*x^14 - 6966*x^13 + 37088*x^12 - 130876*x^11 + 344918*x^10 - 655255*x^9 + 737997*x^8 - 153262*x^7 - 639936*x^6 + 251910*x^5 + 1132096*x^4 - 1113158*x^3 - 443028*x^2 - 27305*x - 125)/(x-1)^13.
Showing 1-5 of 5 results.