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A100391 Prime powers which are local minima of A006530. +0
1
4, 8, 16, 27, 32, 64, 81, 125, 128, 243, 256, 343, 512, 625, 729, 1024, 1331, 2048, 2187, 2197, 3125, 4096, 6561, 8192, 14641, 15625, 16384, 16807, 19683, 24389, 28561, 32768, 50653, 59049, 65536, 68921, 78125, 79507, 83521, 103823, 117649, 130321 (list; graph; listen)
OFFSET

1,1

EXAMPLE

Largest prime factors around 49 are {3,7,5} so 49 is not a member.

While n=343=7^3 is here because the corresponding largest-prime-factors are {19,7,43}.

MATHEMATICA

<<NumberTheory`NumberTheoryFunctions` mxp[x_] :=Max[PrimeFactorList[x]]; lf[x_] :=Length[PrimeFactorList[x]]; ta={{0}}; Do[s1=mxp[n-1]; s=mxp[n]; s2=mxp[n+1]; If[Greater[s1, s]&&Greater[s2, s]&&Equal[lf[n], 1], Print[{n, {s1, s, s2}}]; ta=Append[ta, n]], {n, 1, 512}]; ta=Delete[ta, 1]

CROSSREFS

Cf. A006530, A100390.

Sequence in context: A096296 A068936 A054744 this_sequence A122494 A025197 A008371

Adjacent sequences: A100388 A100389 A100390 this_sequence A100392 A100393 A100394

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Dec 14 2004

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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