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2, 8, 15, 48, 1152, 19200, 62370, 322560, 17418240, 567705600, 2481078600, 16907304960, 1504935936000, 8799558768000, 76435881984000, 819678899239200, 10176845001523200, 2169274855587840000, 215013524533936128000
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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composite = Select[Range[100], CompositeQ]; (* A002808 *)
z = 20;
f[j_]:= composite[[j]];
v[n_]:= Product[Product[f[k] - f[j], {j, 1, k - 1}], {k, 2, n}];
d[n_]:= Product[(i-1)!, {i, 1, n}];
Table[v[n+1]/v[n], {n, z}] (* this sequence *)
Table[v[n]/d[n], {n, z}] (* A203420 *)
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PROG
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(Magma)
A002808:=[n: n in [2..250] | not IsPrime(n)];
(SageMath)
A002808=[n for n in (2..250) if not is_prime(n)]
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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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