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A293263 Number of fixed polyominoes without holes that have a width of n and height of 3. 2
1, 15, 106, 582, 2952, 14488, 69982, 335356, 1600624, 7624266, 36279784, 172546968, 820420150, 3900386212, 18541702744, 88140749906, 418982915000, 1991645550032, 9467293435654, 45002706816100, 213919774521224, 1016864234903874, 4833646472767104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..200

FORMULA

a(n) = 10*a(n-1) - 34*a(n-2) + 49*a(n-3) - 29*a(n-4) + 2*a(n-5) + 10*a(n-6) - 5*a(n-7) - 2*a(n-8) for n > 9.

G.f.: x*(1 + 5*x - 10*x^2 - 17*x^3 + 30*x^4 - 5*x^5 - 14*x^6 + x^7 + x^8)/((1 - x)*(1 - 2*x - x^2)*(1 - 7*x + 12*x^2 - 7*x^3 + 3*x^4 + 2*x^5)).

PROG

(PARI) Vec((1 + 5*x - 10*x^2 - 17*x^3 + 30*x^4 - 5*x^5 - 14*x^6 + x^7 + x^8)/((1 - x)*(1 - 2*x - x^2)*(1 - 7*x + 12*x^2 - 7*x^3 + 3*x^4 + 2*x^5)) + O(x^40));

CROSSREFS

Row 3 of A232103.

Sequence in context: A278781 A275644 A074877 * A202255 A243212 A232124

Adjacent sequences:  A293260 A293261 A293262 * A293264 A293265 A293266

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Oct 04 2017

STATUS

approved

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Last modified October 2 20:53 EDT 2022. Contains 357230 sequences. (Running on oeis4.)