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A272590
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a(n) is the smallest number m such that the multiplicative group modulo m is the direct product of n cyclic groups.
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1
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2, 8, 24, 120, 840, 9240, 120120, 2042040, 38798760, 892371480, 25878772920, 802241960520, 29682952539240, 1217001054108840, 52331045326680120, 2459559130353965640, 130356633908760178920, 7691041400616850556280, 469153525437627883933080, 31433286204321068223516360
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OFFSET
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1,1
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COMMENTS
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Arguably a(1)=3, as the multiplicative group mod 2 has only one element, hence its factorization is the empty product. - Joerg Arndt, May 18 2018
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LINKS
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FORMULA
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a(1) = 2, a(n) = 4 * prod(k=1..n-1, prime(k) ) for n >= 2.
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PROG
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(PARI) a(n)=if(n==1, 2, 4*prod(k=1, n-1, prime(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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STATUS
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approved
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