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A038765
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Next-to-last diagonal of A024462.
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1
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1, 2, 7, 24, 81, 270, 891, 2916, 9477, 30618, 98415, 314928, 1003833, 3188646, 10097379, 31886460, 100442349, 315675954, 990074583, 3099363912, 9685512225, 30218798142, 94143178827, 292889889684, 910050728661, 2824295364810
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| S. J. Cyvin et al., Unbranched catacondensed polygonal systems containing hexagons and tetragons, Croatica Chem. Acta, 69 (1996), 757-774.
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FORMULA
| G.f.: (1-2*x)^2/((1-3*x)^2). Detlef Pauly (dettodet(AT)yahoo.de), Mar 03 2003
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MAPLE
| seq(ceil(1/9*3^n*(5+n)), n=0..50);
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CROSSREFS
| Sequence in context: A132788 A109682 A027124 * A027126 A027128 A099463
Adjacent sequences: A038762 A038763 A038764 * A038766 A038767 A038768
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), May 03 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 03 2000
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