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 A084599 a(1) = 2, a(2) = 3; for n >= 2, a(n+1) is largest prime factor of (Product_{k=1..n} a(k)) - 1. 3
 2, 3, 5, 29, 79, 68729, 3739, 6221191, 157170297801581, 70724343608203457341903, 46316297682014731387158877659877, 78592684042614093322289223662773, 181891012640244955605725966274974474087, 547275580337664165337990140111772164867508038795347198579326533639132704344301831464707648235639448747816483406685904347568344407941 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Like the Euclid-Mullin sequence A000946, but subtracting rather than adding 1 to the product. LINKS Dario Alpern, ECM EXAMPLE a(4)=29 since 2*3*5=30 and 29 is the largest prime factor of 30-1 a(5)=79 since 2*3*5*29=870 and 79 is the largest prime factor of 870-1=869=11*79. CROSSREFS Cf. A000946, A005265, A084598. Essentially the same as A005266. Sequence in context: A215103 A038962 A019400 * A062167 A279189 A107451 Adjacent sequences:  A084596 A084597 A084598 * A084600 A084601 A084602 KEYWORD nonn AUTHOR Marc LeBrun, May 31 2003 EXTENSIONS More terms from Hugo Pfoertner, May 31, 2003, using Dario Alpern's ECM. The next term a(15) is not known. It requires the factorization of the 245-digit composite number which remains after eliminating 7 smaller factors. STATUS approved

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Last modified January 16 11:32 EST 2019. Contains 319188 sequences. (Running on oeis4.)