A100386 - OEIS

%I #12 Oct 19 2017 03:14:37

%S 586951,1473257,4982941,13565441,24954141,25384714,26576686,32026196,

%T 35797623,35953989,37972276,39048260,51755761,58769257,60682681,

%U 71342703,77863117,80826231,84766857,89768134,98363506,110482826,115045547,115898807,120797465

%N Numbers n such that for m=n to n+9, A006530(m) decreases.

%C A006530(n) is the largest prime factor of n.

%H Donovan Johnson, <a href="/A100386/b100386.txt">Table of n, a(n) for n = 1..1000</a>

%e 586951 is here because the largest prime factors of 586951..586960 are 586951,73369,21739,9467,1319,1193,1181,1091,677,29.

%t <<NumberTheory`NumberTheoryFunctions` {ta={{0}},tm=TimeUsed[]}; mxp[x_] :=Max[PrimeFactorList[x]] Do[g=n;s1=mxp[n];s2=mxp[n+1];s3=mxp[n+2];s4=mxp[n+3];s5=mxp[n+4];s6=mxp[n+5]; s7=mxp[n+6];s8=mxp[n+7];s9=mxp[n+8];s10=mxp[n+9]; If[ !Greater[s2,s1]&&!Greater[s3,s2]&&!Greater[s4,s3]&& !Greater[s5,s4]&&!Greater[s6,s5]&&!Greater[s7,s6]&& !Greater[s8,s7]&&!Greater[s9,s8]&&!Greater[s10,s9], Print[{n,{s1,s2,s3,s4,s5,s6,s7,s8,s9,s10}}]; ta=Append[ta,n]],{n,586950,21977000}];ta

%t Position[Partition[Table[FactorInteger[n][[-1,1]],{n,121*10^6}],10,1],_?(Max[Differences[#]]<0&),{1},Heads->False]//Flatten (* _Harvey P. Dale_, Sep 18 2016 *)

%Y Cf. A006530, A070087, A071870, A100385.

%K nonn

%O 1,1

%A _Labos Elemer_, Dec 09 2004

%E Edited by _Don Reble_, Jun 13 2007