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A076509
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Expansion of 3*x*(1-x)*(1+2*x+6*x^2)/(1-24*x^3).
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1
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3, 3, 12, 54, 72, 288, 1296, 1728, 6912, 31104, 41472, 165888, 746496, 995328, 3981312, 17915904, 23887872, 95551488, 429981696, 573308928, 2293235712, 10319560704, 13759414272, 55037657088, 247669456896, 330225942528
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OFFSET
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1,1
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COMMENTS
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Previous name was: 3 people at a party are saying Hello to each other. Person 3 says Hello Hello Hello. Person 1 counts the times Hello has been said and says Hello that number of times. Person 2 says Hello a number of times equal to 2 * the sum of Hello's; then it is Person 3's turn again. Sequence gives the number of Hello's said.
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LINKS
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FORMULA
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G.f.: 3*x*(1-x)*(1+2*x+6*x^2)/(1-24*x^3). [Colin Barker, Jun 07 2012]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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