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A157005
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A Somos-4 variant.
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3
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1, 2, 8, 24, 112, 736, 3776, 40192, 391424, 4203008, 85312512, 1270368256, 32235102208, 1038278549504, 27640704385024, 1549962593927168, 73624753456480256, 4273828146025070592, 435765959975516766208
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Hankel transform of A157004.
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FORMULA
| a(0)=1,a(1)=2,a(2)=8,a(3)=24; for n >= 4, a(n)=(a(n-1)a(n-3)+a(n-2)^2)/a(n-4);
a(n)=2^n*A006720(n+2).
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MATHEMATICA
| RecurrenceTable[{a[0]==1, a[1]==2, a[2]==8, a[3]==24, a[n]==(a[n-1] a[n-3]+a[n-2]^2)/a[n-4]}, a, {n, 20}] (* From Harvey P. Dale, Apr 30 2011 *)
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CROSSREFS
| Sequence in context: A150667 A150668 A150669 * A123775 A052624 A087982
Adjacent sequences: A157002 A157003 A157004 * A157006 A157007 A157008
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Feb 20 2009
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