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 A235425 Numbers n such that between n and the next prime there are gpf(n) numbers, where gpf(n) denotes the largest prime factor of n. 3

%I

%S 8,64,128,625,729,1701,2625,3025,4096,6435,8505,10115,12675,14641,

%T 17303,19343,19683,19845,21125,25515,25725,26325,26741,27783,32768,

%U 33075,33275,34075,35721,38025,39375,42525,43875,50193,59319,60835,61731,70805,75411,75803

%N Numbers n such that between n and the next prime there are gpf(n) numbers, where gpf(n) denotes the largest prime factor of n.

%H Giovanni Resta, <a href="/A235425/b235425.txt">Table of n, a(n) for n = 1..10000</a>

%e 64 = 2^6, whose largest prime factor is 2, is in the sequence because between 64 and 67 (the next prime) there are 2 numbers, 65 and 66.

%t Select[Range[10^5], NextPrime[#] - # == 1 + FactorInteger[#][[-1, 1]] &]

%o (PARI) gpf(n)=n=factor(n)[,1];n[#n]

%o is(n)=nextprime(n)-n==gpf(n)+1 \\ _Charles R Greathouse IV_, Jan 10 2014

%Y Cf. A050765, A105779.

%K nonn

%O 1,1

%A _Giovanni Resta_, Jan 10 2014

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Last modified September 19 16:01 EDT 2020. Contains 337178 sequences. (Running on oeis4.)