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.

A179424 Number of ways to place 4 nonattacking kings on an n X n toroidal board.

Original entry on oeis.org

0, 0, 0, 12, 575, 9837, 63553, 265008, 853497, 2312925, 5532967, 12037068, 24293243, 46125317, 83243925, 143918272, 239811333, 387002853, 607226187, 929346700, 1391111127, 2041198973, 2941608713, 4170413232, 5824920625, 8025278157, 10918558863, 14683371948, 19535039827, 25731386325
Offset: 1

Views

Author

Vaclav Kotesovec, Jan 07 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[x^3 (160 x^9 - 963 x^8 + 2054 x^7 - 1308 x^6 - 963 x^5 - 375 x^4 + 5288 x^3 - 5094 x^2 -467 x - 12) / (x - 1)^9, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)

Formula

Explicit formula: a(n) = 1/24*n^2*(n^6-54*n^4+1019*n^2-6798), n>=5.
G.f.: x^4*(160*x^9 - 963*x^8 + 2054*x^7 - 1308*x^6 - 963*x^5 - 375*x^4 + 5288*x^3 - 5094*x^2 - 467*x - 12)/(x-1)^9.

A179425 Number of ways to place 5 nonattacking kings on an n X n toroidal board.

Original entry on oeis.org

0, 0, 0, 0, 10, 14940, 229908, 1678336, 8155404, 30614620, 96011322, 263506752, 652150382, 1485650012, 3161648520, 6355083264, 12167739256, 22339050588, 39536586430, 67748508480, 112804636266, 183057635420, 290261282204, 450688785408, 686540794500, 1027700020828, 1513897376994, 2197363228480, 3146046781446, 4447496831580
Offset: 1

Views

Author

Vaclav Kotesovec, Jan 07 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[- 2 x^4 (260 x^11 - 1932 x^10 + 6567 x^9 - 16223 x^8 + 38507 x^7 - 77869 x^6 + 102208 x^5 - 61576 x^4 - 15301 x^3 + 33059 x^2 + 7415 x + 5) / (x - 1)^11, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)

Formula

Explicit formula: a(n) = 1/120*n^2*(n^8-90n^6+3155n^4-51450n^2+332544), n>=6.
G.f.: -2x^5*(260x^11 - 1932x^10 + 6567x^9 - 16223x^8 + 38507x^7 - 77869x^6 + 102208x^5 - 61576x^4 - 15301x^3 + 33059x^2 + 7415x + 5)/(x-1)^11.

A179426 Number of ways to place 6 nonattacking kings on an n X n toroidal board.

Original entry on oeis.org

0, 0, 0, 0, 0, 10596, 486668, 7063520, 55345356, 299491100, 1263811604, 4455716184, 13701863604, 37823872044, 95648273100, 224887404416, 497181121100, 1042609380588, 2088337713332, 4017815773400, 7459198321428, 13414493857116, 23444476061772, 39928736913120, 66425550447500, 108162598959740, 172697249542932, 270794133842456, 417578468928308, 634036069773900
Offset: 1

Views

Author

Vaclav Kotesovec, Jan 07 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[4 x^5 (426 x^13 - 4263 x^12 + 22311 x^11 - 82449 x^10 + 220918 x^9 - 391803 x^8 + 369356 x^7 + 10716 x^6 - 382230 x^5 + 163719 x^4 + 387689 x^3 - 390831 x^2 - 87230 x - 2649) / (x - 1)^13, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)

Formula

a(n) = 1/720*n^2*(n^10 -135*n^8 +7525*n^6 -217665*n^4 +3289354*n^2 -20949480), n>=7.
G.f.: 4*x^6*(426*x^13 - 4263*x^12 + 22311*x^11 - 82449*x^10 + 220918*x^9 - 391803*x^8 + 369356*x^7 + 10716*x^6 - 382230*x^5 + 163719*x^4 + 387689*x^3 - 390831*x^2 - 87230*x - 2649)/(x-1)^13.

A179427 Number of ways to place 7 nonattacking kings on an n X n toroidal board.

Original entry on oeis.org

0, 0, 0, 0, 0, 3420, 576856, 19760512, 270487188, 2209065700, 12914201256, 59659859232, 231216019632, 781647658596, 2367858314700, 6553746728448, 16815788711212, 40446802230372, 92003239814224, 199311860224800, 413589922308360, 825997764087012, 1594007700404532, 2982430581363072, 5425904270482500, 9622254525739492, 16669554533555832, 28264133502586912, 46982453295836640, 76676963241363300
Offset: 1

Views

Author

Vaclav Kotesovec, Jan 07 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[- 4 x^5 (1379 x^16 - 18219 x^15 + 124755 x^14 - 553765 x^13 + 1657983 x^12 - 3369984 x^11 + 4870575 x^10 - 6400905 x^9 + 10992208 x^8 - 19069951 x^7 + 21246441 x^6 - 8631071 x^5 - 7797385 x^4 + 8273322 x^3 + 2866693 x^2 + 131389 x + 855) / (x - 1)^15, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)

Formula

Explicit formula: a(n) = 1/5040*n^2*(n^12 -189*n^10 +15295*n^8 -681135*n^6 +17692024*n^4 -255655596*n^2 +1617230880), n>=8.
G.f.: -4*x^6*(1379*x^16 - 18219*x^15 + 124755*x^14 - 553765*x^13 + 1657983*x^12 - 3369984*x^11 + 4870575*x^10 - 6400905*x^9 + 10992208*x^8 - 19069951*x^7 + 21246441*x^6 - 8631071*x^5 - 7797385*x^4 + 8273322*x^3 + 2866693*x^2 + 131389*x + 855)/(x-1)^15.

A179428 Number of ways to place 8 nonattacking kings on an n X n toroidal board.

Original entry on oeis.org

0, 0, 0, 0, 0, 486, 346381, 36285336, 956078397, 12428297150, 104000525596, 643409498286, 3191250652226, 13361641961066, 48905750870775, 160414160371552, 480243686391743, 1330654487994234, 3449609146025210, 8439769551278350, 19624142987739108, 43616849672119790, 93112709811981557, 191696927842663704, 381920049400830625, 738532765420347014, 1389708580432837752, 2550402748009811870, 4573836436177381798, 8029626473495462850
Offset: 1

Views

Author

Vaclav Kotesovec, Jan 07 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[x^5 (17728 x^19 - 301964 x^18 + 2573500 x^17 - 13833040 x^16 + 51521058 x^15 - 143708688 x^14 + 325486412 x^13 - 629393865 x^12 + 996601251 x^11 - 1090603627 x^10 + 426710617 x^9 + 807953488 x^8 - 1328885640 x^7 + 262625618 x^6 + 1106513030 x^5 - 875387697 x^4 - 386005021 x^3 - 30462955 x^2 - 338119 x - 486) / (x - 1)^17, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)

Formula

a(n) = 1/40320*n^2 * (n^14 -252*n^12 +27874*n^10 -1759800*n^8 +68745649*n^6 -1669136028*n^4 +23447322156*n^2 -147931524720), n>=9.
G.f.: x^6*(17728x^19 - 301964x^18 + 2573500x^17 - 13833040x^16 + 51521058x^15 - 143708688x^14 + 325486412x^13 - 629393865x^12 + 996601251x^11 - 1090603627x^10 + 426710617x^9 + 807953488x^8 - 1328885640x^7 + 262625618x^6 + 1106513030x^5 - 875387697x^4 - 386005021x^3 - 30462955x^2 - 338119x - 486)/(x-1)^17.

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.

A180067 Number of ways to place 9 nonattacking kings on an n X n toroidal board.

Original entry on oeis.org

0, 0, 0, 0, 0, 28, 81095, 42752576, 2436444603, 53633024900, 666519047964, 5655962632720, 36502953719310, 191587564345044, 854990702601025, 3346890268570368, 11756179090049177, 37692541754516628, 111774885566128630, 309788198526691600
Offset: 1

Views

Author

Vaclav Kotesovec, Jan 15 2011

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[- x^5 (56520 x^22 - 1215064 x^21 + 12642984 x^20 - 82438064 x^19 + 378510176 x^18 - 1315100032 x^17 + 3593010018 x^16 - 7742517098 x^15 + 12798616135 x^14 - 15614945085 x^13 + 14742135008 x^12 - 17197088896 x^11 + 33440162097 x^10 - 55183782403 x^9 + 50601858342 x^8 - 7249042450 x^7 - 32800069391 x^6 + 23010354469 x^5 + 14572795412 x^4 + 1637985772 x^3 + 41216559 x^2 + 80563 x + 28) / (x - 1)^19, {x, 0, 40}], x] (* Vincenzo Librandi, Jun 01 2013 *)

Formula

a(n) = 1/362880*n^2 * (n^16 -324*n^14 +46914*n^12 -3975048*n^10 +216203169*n^8 -7756575876*n^6 +179987135516*n^4 -2481599151792*n^2 +15651056776320), n>=10.
G.f.: -x^6*(56520x^22 - 1215064x^21 + 12642984x^20 - 82438064x^19 + 378510176x^18 - 1315100032x^17 + 3593010018x^16 - 7742517098x^15 + 12798616135x^14 - 15614945085x^13 + 14742135008x^12 - 17197088896x^11 + 33440162097x^10 - 55183782403x^9 + 50601858342x^8 - 7249042450x^7 - 32800069391x^6 + 23010354469x^5 + 14572795412x^4 + 1637985772x^3 + 41216559x^2 + 80563x + 28)/(x-1)^19.
General asymptotic formula for number of ways to place k nonattacking kings on an n X n toroidal board: n^2k/k! - 9/2*n^(2k-2)/(k-2)! + (243k+47)*n^(2k-4)/(24*(k-3)!) - (243k^2+141k+80)*n^(2k-6)/(16*(k-4)!) + (98415k^3+114210k^2+140645k+101762)*n^(2k-8)/(5760*(k-5)!)-...
Showing 1-7 of 7 results.