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A090531
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Least multiple of n! sandwiched between twin primes, or 0 if no such number exists.
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2
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4, 4, 6, 72, 240, 12240, 35280, 241920, 1088640, 50803200, 1157587200, 14370048000, 298896998400, 2353813862400, 11769069312000, 502146957312000, 4268249137152000, 621030249455616000, 9488317831888896000
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OFFSET
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1,1
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COMMENTS
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Conjecture: No term is zero.
This conjecture is implied by Dickson's conjecture. - Robert Israel, Feb 13 2018
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LINKS
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FORMULA
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MAPLE
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f := proc (n) local k, t; t := factorial(n); for k from t by t do if isprime(k-1) and isprime(k+1) then return k end if end do end proc;
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MATHEMATICA
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lmn[n_]:=Module[{k=n!, m=1}, While[AnyTrue[k*m+{1, -1}, CompositeQ], m++]; k*m]; Join[{4, 4}, Array[lmn, 20, 3]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 27 2020 *)
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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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