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A079028
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a(0) = 1, a(n) = (n+4)*4^(n-1) for n >= 1.
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5
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1, 5, 24, 112, 512, 2304, 10240, 45056, 196608, 851968, 3670016, 15728640, 67108864, 285212672, 1207959552, 5100273664, 21474836480, 90194313216, 377957122048, 1580547964928, 6597069766656, 27487790694400
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| a(n) = det(M(n)) where M(n) is the n X n matrix defined by m(i,i) = 5, m(i,j) = i/j.
Main diagonal of array defined by m(1,j)=j; m(i,1)=i and m(i,j)=m(i-1,j)+3*m(i-1,j-1).
4th binomial transform of (1,1,0,0,0,0,.....). - Paul Barry (pbarry(AT)wit.ie), Mar 07 2003
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LINKS
| F. Disanto, A. Frosini, R. Pinzani and S. Rinaldi, A closed formula for the number of convex permutominoes, arXiv:math.CO/0702550.
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FORMULA
| a(n) = 8*a(n-1)-16*a(n-2), a(0) = 1, a(1) = 5. - Paul Barry (pbarry(AT)wit.ie), Mar 07 2003
a(n)=(1/4)*(n-1)*4^(n-1)+4^(n-1), with n>=1 - Paolo P. Lava (paoloplava(AT)gmail.com), Jul 08 2008
G.f.: (1-3*x)/(1-4*x)^2 . [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 11 2008]
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PROG
| (Other) SAGE:[lucas_number2(n, 4, 0)*n/2^10 for n in xrange(4, 26)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 13 2009]
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CROSSREFS
| Cf. A001792, A006234, A081105, A006234.
Cf. A002697, A034007, A079861, A045891, A087449.
Sequence in context: A183934 A171310 A081104 * A141223 A140766 A026388
Adjacent sequences: A079025 A079026 A079027 * A079029 A079030 A079031
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 01 2003
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