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A220129 1 followed by period 12: (1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11) repeated; offset 0. 2
1, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also the number of tilings of an n X 4 rectangle using integer sided rectangular tiles of area n.

LINKS

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

FORMULA

G.f.: -(10*x^6+11*x^5+16*x^4+9*x^3+7*x^2+2*x+1) / (x^6+x^5+x^4-x^2-x-1).

EXAMPLE

a(6) = 7, because there are 7 tilings of a 6 X 4 rectangle using integer sided rectangular tiles of area 6:

._._._._.  ._._._._.  ._._____.  .___._._.

| | | | |  |     | |  | |     |  |   | | |

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

| | | | |  |     | |  | |     |  |___| | |

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

| | | | |  |     | |  | |     |  |   | | |

|_|_|_|_|  |_____|_|  |_|_____|  |___|_|_|

._.___._.  ._._.___.  .___.___.

| |   | |  | | |   |  |   |   |

| |   | |  | | |   |  |   |   |

| |___| |  | | |___|  |___|___|

| |   | |  | | |   |  |   |   |

| |   | |  | | |   |  |   |   |

|_|___|_|  |_|_|___|  |___|___|

MAPLE

a:= n-> `if`(n=0, 1, [11, 1, 5, 3, 9, 1, 7, 1, 9, 3, 5, 1][irem(n, 12)+1]):

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

CROSSREFS

Row n=4 of A220122.

Sequence in context: A092748 A078302 A199438 * A192039 A305327 A112812

Adjacent sequences:  A220126 A220127 A220128 * A220130 A220131 A220132

KEYWORD

nonn,easy

AUTHOR

Alois P. Heinz, Dec 06 2012

STATUS

approved

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Last modified November 19 16:37 EST 2019. Contains 329323 sequences. (Running on oeis4.)