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A068240
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1/2 the number of colorings of a 4 X 4 square array with n colors.
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2
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1, 3906, 3000366, 414425080, 19064362455, 428429377026, 5861180425996, 55823546748096, 403783634784285, 2353615149832210, 11531349080992026, 48981767072238936, 184656623163700051, 629125059062885490, 1964980839044519640, 5691311662142685376
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OFFSET
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2,2
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LINKS
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FORMULA
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G.f.: -(2507986*x^14 +349887529*x^13 +12282125725*x^12 +158263444274*x^11 +896159384816*x^10 +2455337616143*x^9 +3417678462327*x^8 +2453922059100*x^7 +895941969162*x^6 +158666067383*x^5 +12424532171*x^4 +363949394*x^3 +2934100*x^2 +3889*x+1)*x^2 / (x-1)^17.
a(n) = n*(n-1)*(n^14 -23*n^13 +253*n^12 -1762*n^11 +8675*n^10 -31939*n^9 +90723*n^8 -202160*n^7 +355622*n^6 -492434*n^5 +529770*n^4 -430857*n^3 +251492*n^2 -94782*n +17493)/2.
(End)
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MAPLE
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a:= n-> n*(n-1)*(17493+(-94782+(251492+(-430857+(529770+(-492434 +(355622+(-202160+(90723+(-31939+(8675+(-1762+(253 +(-23+n)*n)*n) *n)*n)*n)*n) *n)*n) *n)*n) *n)*n)*n) /2:
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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