A229598 Voids left when packing boomerangs into n X n coins.

1, 0, 3, 8, 5, 12, 21, 16, 27, 40, 33, 48, 65, 56, 75, 96, 85, 108, 133, 120, 147, 176, 161, 192, 225, 208, 243, 280, 261, 300, 341, 320, 363, 408, 385, 432, 481, 456, 507, 560, 533, 588, 645, 616, 675, 736, 705, 768

Offset: 2

Author

Kival Ngaokrajang, Sep 26 2013

Keywords

• nonn

Comments

The inverse patterns are voids or stars (consist of 4 perimeter parts of coins) appearing in n X n coins using the same rule as A229593.

Examples

			For n = 2, there is no boomerang can be packed into 2X2 coins, there is 1 void left, a(2) = 1.
For n = 3, there are 2 boomerangs can be packed into 3X3 coins with no void left, a(3) = 0.
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Links

• Kival Ngaokrajang, Illustration of initial terms

Crossrefs

Cf. A229093 (Illustration of inverse clubs patterns).

Formula

Empirical g.f.: -x^2*(x+1)*(x^4-2*x^3+5*x^2-2*x+1) / ((x-1)^3*(x^2+x+1)^2). - Colin Barker, Oct 06 2013