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A194605
Number of ways to place 2 nonattacking kings on an n X n X n X n raumschach board (four-dimensional chessboard).
2
0, 0, 0, 2080, 27768, 181032, 807040, 2817240, 8271480, 21328048, 49692672, 106717680, 214322680, 406928280, 736614528, 1279735912, 2145244920, 3484996320, 5506324480, 8487206208, 12794341752, 18904506760, 27429548160, 39145417080, 55025652088, 76279746192
OFFSET
0,4
LINKS
Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1).
FORMULA
a(n) = (n^8 - (3*n-2)^4) / 2 for n>0.
G.f.: 8*x^3*(260+1131*x+750*x^2+335*x^3+75*x^4-30*x^5-x^6)/(1-x)^9. - Bruno Berselli, Aug 31 2011
CROSSREFS
Cf. A194604 for the general d-dimensional case.
Sequence in context: A076581 A183675 A178272 * A233104 A071235 A259414
KEYWORD
nonn,easy
AUTHOR
Andrew Woods, Aug 30 2011
STATUS
approved