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A270063
Number of tilings of a 3 X n rectangle using monominoes and trominoes of any shape.
3
1, 2, 14, 93, 590, 3710, 23509, 148796, 940916, 5952243, 37655502, 238204978, 1506870209, 9532433288, 60301864000, 381467462217, 2413150656124, 15265511608858, 96569119066667, 610893045560410, 3864489168524208, 24446630393071735, 154648573589573678
OFFSET
0,2
LINKS
FORMULA
G.f.: -(x^15 +2*x^14 +5*x^13 -4*x^12 -7*x^11 -21*x^10 +12*x^9 +11*x^8 +24*x^7 -21*x^6 -13*x^5 +16*x^3 +2*x^2 +2*x -1) / (x^18 +2*x^17 +5*x^16 -9*x^15 -21*x^14 -54*x^13 +32*x^12 +46*x^11 +147*x^10 +21*x^9 -40*x^8 -110*x^7 -17*x^6 -11*x^5 -32*x^4 -37*x^3 -8*x^2 -4*x +1).
CROSSREFS
Column k=3 of A270061.
Cf. A134438.
Sequence in context: A341395 A072148 A297474 * A033169 A090410 A066052
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Mar 09 2016
STATUS
approved