|
Search: id:A061991
|
|
|
| A061991 |
|
Number of ways to place 5 nonattacking queens on a 5 X n board. |
|
+0
3
|
|
| 0, 0, 0, 0, 0, 10, 40, 164, 568, 1614, 3916, 8492, 16852, 31100, 54068, 89428, 141812, 216932, 321700, 464348, 654548, 903532, 1224212, 1631300, 2141428, 2773268, 3547652, 4487692, 5618900, 6969308, 8569588, 10453172, 12656372
(list; graph; listen)
|
|
|
OFFSET
|
0,6
|
|
|
LINKS
|
V. Kotesovec, Ways of placing non-attacking queens and kings..., part of "Between chessboard and computer", 1996, pp. 204 - 206.
|
|
FORMULA
|
G.f.: 2*x^5*(4*x^11 - 11*x^10 + 16*x^9 + 7*x^8 - 32*x^7 + 38*x^6 + 6*x^5 + 8*x^4 - 8*x^3 + 37*x^2 - 10*x + 5)/(x - 1)^6; Recurrence: a(n) = 6*a(n - 1) - 15*a(n - 2) + 20*a(n - 3) - 15*a(n - 4) + 6*a(n - 5) - a(n - 6), n >= 17. Explicit formula (V.Kotesovec, 1992): a(n) = n^5 - 30*n^4 + 407*n^3 - 3098*n^2 + 13104*n - 24332, n >= 11.
|
|
CROSSREFS
|
Cf. A061989, A061990.
Sequence in context: A013977 A075060 A002066 this_sequence A060580 A118266 A054885
Adjacent sequences: A061988 A061989 A061990 this_sequence A061992 A061993 A061994
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), May 31 2001
|
|
|
Search completed in 0.002 seconds
|
