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Search: id:A119881
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| 1, 3, 8, 18, 32, 48, 128, 528, 512, -6912, 2048, 357888, 8192, -22351872, 32768, 1903822848, 131072, -209865080832, 524288, 29088886161408, 2097152, -4951498048929792, 8388608, 1015423886523629568, 33554432, -246921480190140874752, 134217728, 70251601603944228323328
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Transform of 3^n under the matrix A119879.
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FORMULA
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a(n)=sum{k=0..n, A119879(n,k)3^k}
a(n) = Sum(binomial(n,k)*B(k,1)*2^(n+k)/(n-k+1), k=0..n). Here B(k,1) are the Bernoulli number A027641(k)/A027642(k) with the exception B(1,1)=1/2. [From Peter Luschny (peter(AT)luschny.de), Dec 14 2008]
a(n) = 2^n |E(n,-1)| where E(n,x) are the Euler polynomials. [From Peter Luschny (peter(AT)luschny.de), Jan 25 2009]
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MAPLE
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a := proc(n) add(binomial(n, k)*bernoulli(k, 1)*2^(n+k)/(n-k+1), k=0..n) end: [From Peter Luschny (peter(AT)luschny.de), Dec 14 2008]
a := n -> 2^n*abs(euler(n, -1)): [From Peter Luschny (peter(AT)luschny.de), Jan 25 2009]
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CROSSREFS
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Sequence in context: A088589 A063597 A004210 this_sequence A075342 A083726 A081489
Adjacent sequences: A119878 A119879 A119880 this_sequence A119882 A119883 A119884
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KEYWORD
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easy,sign
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), May 26 2006
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