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A220131 Number of tilings of an n X 6 rectangle using integer sided rectangular tiles of area n. 2
1, 1, 13, 6, 35, 3, 46, 1, 35, 6, 15, 1, 88, 1, 13, 8, 35, 1, 46, 1, 37, 6, 13, 1, 88, 3, 13, 6, 35, 1, 48, 1, 35, 6, 13, 3, 88, 1, 13, 6, 37, 1, 46, 1, 35, 8, 13, 1, 88, 1, 15, 6, 35, 1, 46, 3, 35, 6, 13, 1, 90, 1, 13, 6, 35, 3, 46, 1, 35, 6, 15, 1, 88, 1, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

1 followed by period 60: (1, 13, ..., 90) repeated; offset 0.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

FORMULA

G.f.: see Maple program.

EXAMPLE

a(3) = 6, because there are 6 tilings of a 3 X 6 rectangle using integer sided rectangular tiles of area 3:

._._._._._._.   ._____._._._.   ._._____._._.

| | | | | | |   |_____| | | |   | |_____| | |

| | | | | | |   |_____| | | |   | |_____| | |

|_|_|_|_|_|_|   |_____|_|_|_|   |_|_____|_|_|

._._._____._.   ._._._._____.   ._____._____.

| | |_____| |   | | | |_____|   |_____|_____|

| | |_____| |   | | | |_____|   |_____|_____|

|_|_|_____|_|   |_|_|_|_____|   |_____|_____|

MAPLE

gf:= -(89*x^16 +90*x^15 +103*x^14 +109*x^13 +144*x^12 +58*x^11 +103*x^10 +91*x^9 +120*x^8 +91*x^7 +103*x^6 +58*x^5 +56*x^4 +21*x^3 +15*x^2 +2*x +1) / (x^16 +x^15 +x^14 +x^13 +x^12 -x^4 -x^3 -x^2 -x -1):

a:= n-> coeff(series(gf, x, n+1), x, n):

seq(a(n), n=0..100);

CROSSREFS

Row n=6 of A220122.

Sequence in context: A300504 A168210 A206612 * A268723 A300942 A160247

Adjacent sequences:  A220128 A220129 A220130 * A220132 A220133 A220134

KEYWORD

nonn,easy

AUTHOR

Alois P. Heinz, Dec 06 2012

STATUS

approved

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Last modified April 22 06:35 EDT 2019. Contains 322329 sequences. (Running on oeis4.)