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 A083663 Least k such that k*n!-1 is prime. 5
 3, 2, 1, 1, 2, 1, 1, 5, 3, 4, 4, 1, 5, 1, 2, 9, 2, 30, 30, 5, 44, 2, 7, 13, 5, 3, 11, 2, 14, 1, 7, 1, 1, 30, 16, 22, 36, 1, 38, 13, 22, 6, 36, 17, 36, 40, 31, 25, 38, 13, 4, 32, 22, 154, 10, 27, 7, 121, 9, 33, 19, 19, 4, 26, 100, 18, 46, 75, 21, 11, 34, 75, 38, 7, 45, 3, 19, 13, 59, 39, 72 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..600 FORMULA a(n) = A053989(n!) = (A084730(n)+1)/n!. - Robert Israel, Nov 23 2023 MAPLE f:= proc(n) local w, k; w:= n!; for k from 1 do if isprime(k*w-1) then return k fi od end proc: map(f, [\$1..100]); # Robert Israel, Nov 23 2023 PROG (PARI) a(n)=if(n<1, 0, k=1; while(isprime(k*n!-1)==0, k++); k) CROSSREFS Cf. A035093, A053989, A084730. Sequence in context: A140056 A240239 A247044 * A085427 A172130 A202449 Adjacent sequences: A083660 A083661 A083662 * A083664 A083665 A083666 KEYWORD nonn AUTHOR Benoit Cloitre, Jun 14 2003 STATUS approved

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Last modified September 17 12:00 EDT 2024. Contains 375987 sequences. (Running on oeis4.)