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A109897
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Group the natural numbers so that every 2n-th group product is divisible by the single number in the next group. (1), (2,3,4,5), (6), (7,8,9,10,11), (12), (13,14,15,16,17,18,19),(20), (21,22,23,24,25,26,27),(28),... Sequence contains the product of terms in the 2n-th group.
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3
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120, 55440, 253955520, 4475671200, 33891580800, 7146019520640, 106137499051584000, 240679032790296606105600, 74684882115043200, 230656425830328960, 66654064122818055916032000, 171176782669200, 282328002094320, 126639913316232476160000, 859891329773280
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(2) = 7*8*9*10*11 = 55440.
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PROG
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(PARI) m=1; for(k=2, 150, if(m%k==0, print1(m", "); m=1, m*=k))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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