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 A152075 a(n) = the smallest prime p > prime(n) such that p - prime(n) is squarefree, where prime(n) is the n-th prime. 3

%I

%S 3,5,7,13,13,19,19,29,29,31,37,43,43,53,53,59,61,67,73,73,79,89,89,

%T 103,103,103,109,109,131,127,137,137,139,149,151,157,163,173,173,179,

%U 181,191,193,199,199,229,233,229,229,239,239,241,251,257,263,269,271,277

%N a(n) = the smallest prime p > prime(n) such that p - prime(n) is squarefree, where prime(n) is the n-th prime.

%C Indices for which a(n)<a(n-1) are 30, 48, 66, 80, 95, 100, 125, 127, 132, 137, 150, 157, 159, 193,... - _M. F. Hasler_, Nov 23 2008

%H Michael De Vlieger, <a href="/A152075/b152075.txt">Table of n, a(n) for n = 1..10000</a>

%t nxtp[n_]:=NestWhile[NextPrime[#]&,n,!SquareFreeQ[#-n]&]; nxtp/@Prime[Range[60]] (* _Harvey P. Dale_, Apr 23 2011 *)

%o (PARI) A152075(n)=local( p=prime(n), q=p); until( issquarefree(q-p), q=nextprime(q+1)); q \\ _M. F. Hasler_, Nov 23 2008

%Y Cf. A152076.

%K nonn

%O 1,1

%A _Leroy Quet_, Nov 23 2008

%E Terms beyond a(13) from _M. F. Hasler_ and _Ray Chandler_, Nov 23 2008

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Last modified October 13 23:58 EDT 2019. Contains 327986 sequences. (Running on oeis4.)