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Search: id:A109213
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| A109213 |
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Product of a(n-2) and digit reversal of a(n-1). |
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+0
2
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| 1, 2, 2, 4, 8, 32, 184, 15392, 5400584, 74651892640, 25003708306137848, 6335942056759761366725617280, 20682199297864337408779128828731176793076928
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OFFSET
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1,2
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COMMENT
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Cf. A000301 a(n) = a(n-1)*a(n-2), A004086 R(n) = digit reversal of n, A109214 a(n)=a(n-1)*R(a(n-2)).
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FORMULA
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a(n)=a(n-2)*R(a(n-1)).
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EXAMPLE
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a(5)=8, a(6)=32, R(32)=23, hence a(7)=8*23=184; R(184)=841, a(8)=32*841=15392, etc.
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MATHEMATICA
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a[1]=1; a[2]=2; a[n_]:=a[n]=a[n-2]*FromDigits[Reverse[IntegerDigits[a[n-1]]]]; A109213=Table[a[n], {n, 13}]
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CROSSREFS
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Cf. A000301, A004086, A109214.
Sequence in context: A096096 A100799 A070323 this_sequence A109214 A000301 A124439
Adjacent sequences: A109210 A109211 A109212 this_sequence A109214 A109215 A109216
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KEYWORD
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base,nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Jun 22 2005
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