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Search: id:A114480
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| A114480 |
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Kekule numbers for certain benzenoids. |
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+0
1
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| 4, 50, 650, 8500, 111250, 1456250, 19062500, 249531250, 3266406250, 42757812500, 559707031250, 7326660156250, 95907226562500, 1255441894531250, 16433947753906250, 215123168945312500, 2815998840332031250
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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S. J. Cyvin and I. Gutman, Kekule structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 205).
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FORMULA
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a(n)=2[(sqrt(5)+2)((15+5sqrt(5))/2)^(n-1)+(sqrt(5)-2)((15-5sqrt(5))/2)^(n-1)]/sqrt(5).
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MAPLE
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a:=2*((sqrt(5)+2)*((15+5*sqrt(5))/2)^(n-1)+(sqrt(5)-2)*((15-5*sqrt(5))/2)^(n-1))/sqrt(5): seq(expand(a(n)), n=1..20);
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CROSSREFS
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Sequence in context: A027533 A048559 A028455 this_sequence A123356 A139087 A026865
Adjacent sequences: A114477 A114478 A114479 this_sequence A114481 A114482 A114483
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 30 2005
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