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Search: id:A080929
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| A080929 |
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Sequence associated with a(n)=2*a(n-1)+k(k+2)a(n-2). |
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+0
10
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| 1, 3, 12, 40, 120, 336, 896, 2304, 5760, 14080, 33792, 79872, 186368, 430080, 983040, 2228224, 5013504, 11206656, 24903680, 55050240, 121110528, 265289728, 578813952, 1258291200, 2726297600, 5888802816, 12683575296, 27246198784
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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The third column of number triangle A080928
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FORMULA
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G.f.: (1-x)(1-2x+4x^2)/(1-2x)^3
For n>0, a(n) = (n+1)(n+2)2^(n-2). - Ralf Stephan, Jan 16 2004
a(n)=ceil(n*(n+1)*2^(n-3)), n>=1 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 23 2006
ceil(binomial(n+2,2)*2^(n-1)). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 01 2006
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MAPLE
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[seq (ceil(binomial(n+2, 2)*2^(n-1)), n=0..27)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 01 2006
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CROSSREFS
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Essentially the same as A052482.
Cf. A082140, A082141, A082138, A082139, A080951, A080929, A057711.
Sequence in context: A032093 A007993 A052482 this_sequence A061136 A027991 A120304
Adjacent sequences: A080926 A080927 A080928 this_sequence A080930 A080931 A080932
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Feb 26 2003
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