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 A172130 a(n) = the smallest k such that n(n+1)(n+2)...(n+k-1)-1 is a prime 1
 3, 2, 1, 1, 2, 1, 3, 1, 2, 2, 2, 1, 2, 1, 2, 2, 3, 1, 2, 1, 2, 3, 3, 1, 17, 2, 4, 2, 6, 1, 2, 1, 10, 3, 2, 9, 3, 1, 2, 3, 2, 1, 4, 1, 2, 2, 3, 1, 4, 2, 8, 7, 2, 1, 2, 2, 3, 3, 2, 1, 11, 1, 3, 2, 2, 2, 5, 1, 3, 2, 11, 1, 4, 1, 3, 2, 7, 7, 5, 1, 4, 38, 2, 1, 2, 2, 7, 9, 2, 1, 4, 4, 2, 2, 4, 2, 3, 1, 14, 2, 2, 1, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(534) = 624 is particularly large. LINKS Table of n, a(n) for n=1..103. MATHEMATICA a[n_] := Block[{}, For[s = n; k = 1, ! PrimeQ[s - 1], s *= n + k; k++ ]; k]; Table[a[n], {n, 1, 300}] CROSSREFS Cf. A172125, A172133, A087564 Sequence in context: A247044 A083663 A085427 * A202449 A326613 A288627 Adjacent sequences: A172127 A172128 A172129 * A172131 A172132 A172133 KEYWORD nonn AUTHOR Cheng Zhang (cz1(AT)rice.edu), Jan 26 2010, Mar 03 2010 STATUS approved

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Last modified December 5 21:07 EST 2023. Contains 367594 sequences. (Running on oeis4.)