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Search: id:A113569
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| A113569 |
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Least number, k which is a multiple of a primorial, such that p-n*k, p-(n-1)k, p-(n-2)k, ... p-2k, p-k, p, p+k, p+2k, ... p+(n-2)k, p+(n-1)k and p+n*k are all prime with p being the k-th prime. |
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OFFSET
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1,1
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EXAMPLE
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a(1)=2 which is a multiple of a primorial.
a(2)=6 because p=13, and p-6=7 & p+6=19 all of which are prime and 6 is of the form 2*3*m, A002110.
a(3)=720 because p=5443, and p-720=4723, p-2*720=4003, p+720=6163 & p+2*720=6883 all of which are prime and 720 is of the form 2*3*5*m.
a(4)=252420 because p
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MATHEMATICA
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f[n_] := Block[{p = Fold[Times, 1, Prime[ Range[ n]]]},
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CROSSREFS
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Cf. A064403, A112530.
Sequence in context: A110795 A067107 A047690 this_sequence A007338 A046857 A129454
Adjacent sequences: A113566 A113567 A113568 this_sequence A113570 A113571 A113572
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KEYWORD
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hard,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 10 2005
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