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 A242064 Smallest k such that the union of {A242033(i): 1 <= i <= k} and {A242034(i): 1 <= i <= k} includes all primes {3, ..., prime(n)}. 3
 1, 2, 9, 9, 36, 36, 81, 220, 220, 386, 386, 386, 434, 521, 896, 896, 896, 1167, 1167, 1695, 2065, 2096, 2096, 2968, 2968, 2968, 2968, 3341, 4561, 4561, 4561, 4561, 4672, 4672, 5964, 6203, 7158, 8294, 8294, 8294, 8740, 8740, 10452, 10452, 11075, 11075, 12092 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 LINKS MATHEMATICA lpf[n_]:=lpf[n]=First[First[FactorInteger[n]]]; (*least prime factor*) A242033=Map[lpf[#-1]&, Select[Range[6, 100000, 2], lpf[#-1]lpf[#-3]&](*A243937*)]; pos={}; NestWhile[#+1&, 2, (AppendTo[pos, Min[Position[A242033, Prime[#], 1, 1], Position[A242034, Prime[#], 1, 1]/.{}->0]]; !Last[pos]==0)&]; A242064=Rest[FoldList[Max, -Infinity, Flatten[pos]]] (* Peter J. C. Moses, Aug 14 2014 *) CROSSREFS Cf. A242033, A242034, A242036, A242037. Sequence in context: A198942 A168333 A238412 * A109322 A000587 A014182 Adjacent sequences:  A242061 A242062 A242063 * A242065 A242066 A242067 KEYWORD nonn AUTHOR Vladimir Shevelev, Aug 13 2014 EXTENSIONS More terms from Peter J. C. Moses, Aug 14 2014 STATUS approved

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Last modified October 15 22:25 EDT 2019. Contains 328038 sequences. (Running on oeis4.)