A172229 -id:A172229 - cp's OEIS frontend

A371967 Irregular triangle T(r,w) read by rows: number of ways of placing w non-attacking wazirs on a 3 X r board.

1, 1, 3, 1, 1, 6, 8, 2, 1, 9, 24, 22, 6, 1, 1, 12, 49, 84, 61, 18, 2, 1, 15, 83, 215, 276, 174, 53, 9, 1, 1, 18, 126, 442, 840, 880, 504, 158, 28, 2, 1, 21, 178, 792, 2023, 3063, 2763, 1478, 472, 93, 12, 1, 1, 24, 239, 1292, 4176, 8406, 10692, 8604, 4374, 1416, 297, 38, 2, 1, 27, 309

Offset: 0

R. J. Mathar, Apr 14 2024

			The triangle starts with r>=0 rows and w>=0 wazirs as
  1 ;
  1 3 1 ;
  1 6 8 2  ;
  1 9 24 22 6 1 ;
  1 12 49 84 61 18 2  ;
  1 15 83 215 276 174 53 9 1 ;
  1 18 126 442 840 880 504 158 28 2  ;
  1 21 178 792 2023 3063 2763 1478 472 93 12 1 ;
  1 24 239 1292 4176 8406 10692 8604 4374 1416 297 38 2  ;
  1 27 309 1969 7731 19591 32716 36257 26674 13035 4264 945 142 15 1 ;
  ...

Alois P. Heinz, Rows r = 0..165 (first 17 rows from R. J. Mathar)
R. J. Mathar, Bivariate Generating Functions for Non-attacking Wazirs on Rectangular Boards
Jacob A. Siehler, Selections without adjacency on a rectangular grid, arXiv:1409.3869 [math.CO] (2014) Table 2.
Wikipedia, Wazir (chess)

Cf. A051736 (row sums), A035607 (on 2Xr board), A011973 (on 1Xr board), A232833 (on rXr board).
T(n,n) gives A371978.
Row maxima give A371979.
Cf. A007494.

b:= proc(n, l) option remember; `if`(n=0, 1,
      add(`if`(Bits[And](j, l)>0, 0, expand(b(n-1, j)*
      x^add(i, i=Bits[Split](j)))), j=[0, 1, 2, 4, 5]))
    end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n, 0)):
seq(T(n), n=0..10);  # Alois P. Heinz, Apr 14 2024

b[n_, l_] := b[n, l] = If[n == 0, 1, Sum[If[BitAnd[j, l] > 0, 0, Expand[b[n - 1, j]*x^DigitCount[j, 2, 1]]], {j, {0, 1, 2, 4, 5}}]];
T[n_] := CoefficientList[b[n, 0], x];
Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Jun 05 2024, after Alois P. Heinz *)

T(r,0) = 1.
T(r,1) = 3*r.
T(r,2) = A064225(r-1).
T(r,3) = A172229(r).
T(r,4) = 27*r^4/8 -117*r^3/4 +829*r^2/8 -715*r/4 +126. [Siehler Table 3]
T(3,w) = A232833(3,w).
G.f.: (1+x*y) *(1 +x*y +x*y^2 -x^2*y^3)/(1 -x -x*y -x^2*y^3 -2*x^2*y -3*x^2*y^2 -x^3*y^2 +x^3*y^4 +x^4*y^4). - R. J. Mathar, Apr 21 2024

A172230 Number of ways to place 4 nonattacking wazirs on a 4 X n board.

Original entry on oeis.org

0, 2, 61, 405, 1502, 4072, 9091, 17791, 31660, 52442, 82137, 123001, 177546, 248540, 339007, 452227, 591736, 761326, 965045, 1207197, 1492342, 1825296, 2211131, 2655175, 3163012, 3740482, 4393681, 5128961, 5952930, 6872452, 7894647

Offset: 1

Vaclav Kotesovec, Jan 29 2010

Wazir is a (fairy chess) leaper [0,1].

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
V. Kotesovec, Number of ways of placing non-attacking queens and kings on boards of various sizes
Eric Weisstein's World of Mathematics, Grid Graph
Wikipedia, Wazir (chess)

Cf. A172227, A172229, A061990.

CoefficientList[Series[- x (4 x^5 + 12 x^4 + 67 x^3 + 120 x^2 + 51 x + 2) / (x - 1)^5, {x, 0, 50}], x] (* Vincenzo Librandi, May 28 2013 *)

a(n) = (64*n^4 - 432*n^3 + 1235*n^2 - 1797*n + 1122)/6, n>=3.

G.f.: -x^2*(4*x^5+12*x^4+67*x^3+120*x^2+51*x+2)/(x-1)^5. - Vaclav Kotesovec, Mar 25 2010

More terms from Vincenzo Librandi, May 28 2013

A172231 Number of ways to place 5 nonattacking wazirs on a 5 X n board.

Original entry on oeis.org

0, 2, 174, 1998, 10741, 38438, 107004, 251354, 522528, 990816, 1748883, 2914894, 4635639, 7089658, 10490366, 15089178, 21178634, 29095524, 39224013, 51998766

Offset: 1

Vaclav Kotesovec, Jan 29 2010

Wazir is a (fairy chess) leaper [0,1].

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
V. Kotesovec, Number of ways of placing non-attacking queens and kings on boards of various sizes
Eric Weisstein's World of Mathematics, Grid Graph
Wikipedia, Wazir (chess)

Cf. A172228, A172229, A172230, A061991.

CoefficientList[Series[x (5 x^7 + 8 x^6 + 129 x^5 + 512 x^4 + 1323 x^3 + 984 x^2 + 162 x + 2) / (x - 1)^6, {x, 0, 50}], x] (* Vincenzo Librandi, May 28 2013 *)

a(n) = (625*n^5-5750*n^4+23535*n^3-54202*n^2+70640*n-41616)/24, n>=4.

G.f.: x^2*(5*x^7+8*x^6+129*x^5+512*x^4+1323*x^3+984*x^2+162*x+2)/(x-1)^6. - Vaclav Kotesovec, Mar 25 2010

A172232 Number of ways to place 6 nonattacking wazirs on a 6 X n board.

Original entry on oeis.org

0, 2, 504, 10010, 78052, 368868, 1280832, 3612344, 8774380, 19049692, 37898664, 70311824, 123209012, 205885204, 330502992, 512631720, 771833276, 1132294540, 1623506488, 2280989952, 3147068036, 4271685188, 5713272928, 7539662232, 9829042572, 12670967612

Offset: 1

Vaclav Kotesovec, Jan 29 2010

Wazir is a (fairy chess) leaper [0,1].

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
V. Kotesovec, Number of ways of placing non-attacking queens and kings on boards of various sizes
Eric Weisstein's World of Mathematics, Grid Graph
Wikipedia, Wazir (chess)

Cf. A172229, A172230, A172231, A061992.

CoefficientList[Series[- 2 x (3 x^9 - 5 x^8 + 100 x^7 + 354 x^6 + 2548 x^5 + 7572 x^4 + 9248 x^3 + 3262 x^2 + 245 x + 1) / (x - 1)^7, {x, 0, 50}], x] (* Vincenzo Librandi, May 28 2013 *)

a(n) = 2*(486*n^6 -5670*n^5 +30240*n^4 -95230*n^3 +187899*n^2 -220775*n +120540) / 15, n>=5.

G.f.: -2*x^2 * (3*x^9 -5*x^8 +100*x^7 +354*x^6 +2548*x^5 +7572*x^4 +9248*x^3 +3262*x^2 +245*x +1) / (x-1)^7. - Vaclav Kotesovec, Mar 25 2010

A172234 Number of ways to place 7 nonattacking wazirs on a 7 X n board.

Original entry on oeis.org

0, 2, 1478, 50726, 573797, 3581924, 15516804, 52550366, 149162199, 370817854, 831571604, 1717417198, 3316210152, 6054985120, 10545491888, 17638773534, 28489610297, 44631652698, 68064067456, 101350519742, 147731315314, 211249526076, 296891922604, 410745537182

Offset: 1

Vaclav Kotesovec, Jan 29 2010

Wazir is a (fairy chess) leaper [0,1].

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
V. Kotesovec, Number of ways of placing non-attacking queens and kings on boards of various sizes
Eric Weisstein's World of Mathematics, Grid Graph
Wikipedia, Wazir (chess)

Cf. A172229, A172230, A172231, A172232, A061993.

CoefficientList[Series[x (7 x^11 - 48 x^10 + 370 x^9 + 40 x^8 + 8541 x^7 + 45282 x^6 + 190420 x^5 + 329248 x^4 + 209261 x^3 + 38958 x^2 + 1462 x+2) / (x - 1)^8, {x, 0, 50}], x] (* Vincenzo Librandi, May 29 2013 *)

a(n) = (117649*n^7-1663893*n^6+10942729*n^5-43685355*n^4+114945646*n^3-199980312*n^2+213228096*n-107390880)/720, n>=6.
For any fixed value of k > 1, a(n) = 1/k!*(kn)^k - (k-1)(5k-2)/2/k!*(kn)^(k-1) + ...
G.f.: x^2*(7*x^11-48*x^10+370*x^9+40*x^8+8541*x^7+45282*x^6+190420*x^5 +329248*x^4+209261*x^3+38958*x^2+1462*x+2)/(x-1)^8. - Vaclav Kotesovec, Mar 25 2010

More terms from Vincenzo Librandi, May 29 2013

A178410 Number of ways to place 8 nonattacking wazirs on an 8 X n board.

Original entry on oeis.org

0, 2, 4374, 259289, 4255370, 35093344, 189681689, 771464278, 2559099153, 7285273805, 18416621598, 42342480425, 90097012004, 179755977430, 339666241815, 612682858064, 1061605357051, 1776021648675, 2880784715492

Offset: 1

Vaclav Kotesovec, May 27 2010

Wazir is a (fairy chess) leaper [0,1].

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
V. Kotesovec, Non-attacking chess pieces, 6ed, 2013

Cf. A172229, A172230, A172231, A172232, A172234.

CoefficientList[Series[- x (8 x^13 - 112 x^12 + 870 x^11 - 2812 x^10 + 15019 x^9 + 41114 x^8 + 494109 x^7 + 2357839 x^6 + 5805509 x^5 + 5762254 x^4 + 2079065 x^3 + 219995 x^2 + 4356 x + 2) / (x - 1)^9, {x, 0, 50}], x] (* Vincenzo Librandi, May 31 2013 *)

a(n) = (1048576*n^8 -17432576*n^7 +136349696*n^6 -658958720*n^5 +2161896569*n^4 -4945969574*n^3 +7719028159*n^2 -7516702410*n +3494080800) / 2520, n >= 7.

G.f.: -x^2 * (8*x^13 -112*x^12 +870*x^11 -2812*x^10 +15019*x^9 +41114*x^8 +494109*x^7 +2357839*x^6 +5805509*x^5 +5762254*x^4 +2079065*x^3 +219995*x^2 +4356*x +2) / (x-1)^9.

cp's OEIS Frontend

A371967 Irregular triangle T(r,w) read by rows: number of ways of placing w non-attacking wazirs on a 3 X r board.

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A172230 Number of ways to place 4 nonattacking wazirs on a 4 X n board.

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A172231 Number of ways to place 5 nonattacking wazirs on a 5 X n board.

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A172232 Number of ways to place 6 nonattacking wazirs on a 6 X n board.

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A172234 Number of ways to place 7 nonattacking wazirs on a 7 X n board.

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A178410 Number of ways to place 8 nonattacking wazirs on an 8 X n board.

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