■日本の畳(その14)
m\n 1 2 3 4 5 6 7 8
1 0 1 0 1 0 1 0 1
2 1 2 3 4 6 9 13 19
3 0 3 0 4 0 6 0 10
4 1 4 4 2 3 3 3 5
5 0 6 0 3 0 2 0 2
6 1 9 6 3 2 2 2 1
7 0 13 0 3 0 2 0 2
8 1 19 10 5 2 1 2 2
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[1]4×7の部屋に14枚の畳を敷く場合,その敷き方の数は?
(1+z)(1+z^2+z^4)/(1−z^3−z^5)
=1+z+z^2+z^3+z^4+z^5
+z^3+z^4+z^5+z^6+z^7+z^8
+z^5+z^6+z^7+z^8+z^9+z^10
+z^6+z^7+z^8+z^9+z^10+z^11
+2z^8+2z^9+2z^10+2z^11+2z^12+2z^13+・・・
=1+z+z^2+2z^3+2z^4+3z^5+3z^6+3z^7+5z^8+4^9+4z^10+3z^11+2z^12+2z^13+・・・
z^5からz^7の係数は正しく求められている.
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[2]5×6の部屋に15枚の畳を敷く場合,その敷き方の数は?
(1+z^4+z^6)/(1−z^4−z^6)
1/(1−z^4−z^6)=1+z^4+z^6+(z^4+z^6)^2+・・・
=1+z^4+z^6+z^8+2z^10+・・・
(1+z^4+z^6)/(1−z^4−z^6)
=1+z^4+z^6
+z^4 +z^8+z^10
+z^6 +z^10+z^12
+z^8 +z^12+z^14+・・・
=1+2z^4+2z^6+2z^8+2z^10+2z^12+・・・
z^5からz^8の係数は正しく求められている.
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