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A013620
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Triangle of coefficients in expansion of (2+3x)^n.
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6
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1, 2, 3, 4, 12, 9, 8, 36, 54, 27, 16, 96, 216, 216, 81, 32, 240, 720, 1080, 810, 243, 64, 576, 2160, 4320, 4860, 2916, 729, 128, 1344, 6048, 15120, 22680, 20412, 10206, 2187, 256, 3072, 16128, 48384, 90720, 108864, 81648, 34992, 6561, 512
(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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LINKS
| Index entries for triangles and arrays related to Pascal's triangle
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FORMULA
| G.f.: 1 / [1 - x(2+3y)].
T(n,k) = A007318(n,k) * A036561(n,k). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 14 2006
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EXAMPLE
| 1;
2,3;
4,12,9;
8,36,54,27;
16,96,216,216,81;
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PROG
| (Haskell)
a013620 n = a013620_list !! n
a013620_list = concat $ iterate ([2, 3] *) [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. A038220, A000079, A000244, A013613.
Sequence in context: A116054 A099527 A096864 * A119799 A036779 A037339
Adjacent sequences: A013617 A013618 A013619 * A013621 A013622 A013623
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KEYWORD
| tabl,nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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