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A242037 a(n) is the smallest k such that in the interval [1,k] of sequence A242034 all odd primes <= prime(n) are present. 4

%I

%S 1,2,23,23,63,63,120,228,228,386,460,460,602,896,1096,1096,1416,1416,

%T 1416,3158,3158,3158,3204,3438,3438,3966,3966,3966,8229,8229,8229,

%U 8229,8229,8229,8229,8229,8229,8294,8593,8593,11125,11125,11559,11559,12216,13594

%N a(n) is the smallest k such that in the interval [1,k] of sequence A242034 all odd primes <= prime(n) are present.

%t lpf[n_]:=lpf[n]=First[First[FactorInteger[n]]]; (* least prime factor *)

%t A242034=Map[lpf[#-3]&,Select[Range[6,100000,2],lpf[#-1]>lpf[#-3]&](*A243937*)];

%t pos={};NestWhile[#+1&,2,(AppendTo[pos,Position[A242034,Prime[#],1,1]];!Last[pos]=={})&];

%t A242037=Rest[FoldList[Max,-Infinity,Flatten[pos]]] (* _Peter J. C. Moses_, Aug 14 2014 *)

%Y Cf. A245024, A243937, A242033, A242034, A242036.

%K nonn

%O 2,2

%A _Vladimir Shevelev_, Aug 12 2014

%E More terms from _Peter J. C. Moses_, Aug 12 2014

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Last modified October 23 12:53 EDT 2019. Contains 328345 sequences. (Running on oeis4.)