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A103998 Number of dimer tilings of a 4 x 2n Moebius strip. 2
1, 11, 71, 539, 4271, 34276, 276119, 2226851, 17965151, 144948419, 1169523076, 9436433171, 76139155439, 614339685971, 4956888901511, 39995380044004, 322708555336511, 2603821045832171, 21009309912323639 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
G.f.: (1-25x^2+22x^3-3x^4)/(1-11x+25x^2-11x^3+x^4).
a(0)=1, a(1)=11, a(2)=71, a(3)=539, a(4)=4271, a(n)=11*a(n-1)-25*a(n-2)+ 11*a(n-3)-a(n-4). - Harvey P. Dale, Jun 15 2011
MATHEMATICA
Join[{1}, LinearRecurrence[{11, -25, 11, -1}, {11, 71, 539, 4271}, 40]] (* or *) CoefficientList[ Series[ (1-25x^2+22x^3-3x^4)/ (1-11x+ 25x^2- 11x^3+x^4), {x, 0, 40}], x] (* Harvey P. Dale, Jun 15 2011 *)
CROSSREFS
Cf. Second row of array A103997.
Sequence in context: A199488 A068847 A139185 * A160587 A338416 A034196
KEYWORD
nonn
AUTHOR
Ralf Stephan, Feb 26 2005
STATUS
approved

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Last modified May 30 02:46 EDT 2024. Contains 372957 sequences. (Running on oeis4.)