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A038220
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Triangle whose (i,j)-th entry is binomial(i,j)*3^(i-j)*2^j.
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6
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1, 3, 2, 9, 12, 4, 27, 54, 36, 8, 81, 216, 216, 96, 16, 243, 810, 1080, 720, 240, 32, 729, 2916, 4860, 4320, 2160, 576, 64, 2187, 10206, 20412, 22680, 15120, 6048, 1344, 128, 6561, 34992, 81648, 108864, 90720, 48384, 16128, 3072, 256
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Row sums give A000351; central terms give A119309. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 14 2006
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REFERENCES
| B. N. Cyvin et al., Isomer enumeration of unbranched catacondensed polygonal systems with pentagons and heptagons, Match, No. 34 (Oct 1996), pp. 109-121.
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LINKS
| Index entries for triangles and arrays related to Pascal's triangle
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FORMULA
| T(n,k) = A007318(n,k) * A036561(n,k). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 14 2006
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PROG
| (Haskell)
a038220 n = a038220_list !! n
a038220_list = concat $ iterate ([3, 2] *) [1]
instance Num a => Num [a] where
fromInteger k = [fromInteger k]
(p:ps) + (q:qs) = p + q : ps + qs
ps + qs = ps ++ qs
(p:ps) * qs'@(q:qs) = p * q : ps * qs' + [p] * qs
_ * _ = []
-- Reinhard Zumkeller, Apr 02 2011
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CROSSREFS
| Cf. A013620, A000079, A000244, A013613, A038221.
Sequence in context: A197831 A152049 A099887 * A053151 A053088 A077898
Adjacent sequences: A038217 A038218 A038219 * A038221 A038222 A038223
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KEYWORD
| nonn,tabl,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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