A250663 Number of tilings of a 12 X n rectangle using 2n hexominoes of shape I.

1, 1, 1, 1, 1, 1, 9, 19, 31, 45, 61, 79, 196, 419, 786, 1341, 2134, 3221, 5789, 10995, 20621, 37149, 63931, 105379, 180201, 319826, 578034, 1040971, 1840549, 3171726, 5465324, 9529019, 16830425, 29914626, 53016504, 92934619, 161999425, 282619059, 495436514

Offset

0,7

Links

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

Wikipedia, Hexomino

Formula

G.f.: See Maple program.

Maple

gf:= -(x^15-x^12-2*x^10-2*x^9+x^7+2*x^6+x^5+x^4+x^3-1) *(x-1)^5 *(x+1)^5 *(x^2+x+1)^5 *(x^2-x+1)^5 / (x^51 -x^48 -3*x^46 -8*x^45 +2*x^43 +8*x^42 +3*x^41 +18*x^40 +28*x^39 -x^38 -11*x^37 -29*x^36 -15*x^35 -45*x^34
-56*x^33 +5*x^32 +24*x^31 +61*x^30 +30*x^29 +60*x^28 +70*x^27 -10*x^26 -25*x^25 -80*x^24 -30*x^23 -45*x^22 -61*x^21 +10*x^20 +10*x^19 +71*x^18 +15*x^17 +28*x^16 +38*x^15 -5*x^14 -2*x^13 -43*x^12 -8*x^11 -8*x^10 -13*x^9 +x^8 -4*x^7 +14*x^6 +x^3 +x -1):
a:= n-> coeff(series(gf, x, n+1), x, n):
seq(a(n), n=0..40);

Crossrefs

Column k=6 of A250662.

Cf. A251075.

Sequence in context: A056126 A190513 A190576 * A274590 A051811 A034056

Adjacent sequences: A250660 A250661 A250662 * A250664 A250665 A250666

Keyword

nonn,easy

Author

Alois P. Heinz, Nov 26 2014

Status

approved