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A152075
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a(n) = the smallest prime p > p(n) such that p - p(n) is squarefree, where p(n) is the n-th prime.
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3
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3, 5, 7, 13, 13, 19, 19, 29, 29, 31, 37, 43, 43, 53, 53, 59, 61, 67, 73, 73, 79, 89, 89, 103, 103, 103, 109, 109, 131, 127, 137, 137, 139, 149, 151, 157, 163, 173, 173, 179, 181, 191, 193, 199, 199, 229, 233, 229, 229, 239, 239, 241, 251, 257, 263, 269, 271, 277
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Indices for which a(n)<a(n-1) are 30, 48, 66, 80, 95, 100, 125, 127, 132, 137, 150, 157, 159, 193,... [From M. F. Hasler (www.univ-ag.fr/~mhasler), Nov 23 2008]
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MATHEMATICA
| nxtp[n_]:=NestWhile[NextPrime[#]&, n, !SquareFreeQ[#-n]&]; nxtp/@Prime[Range[60]] (* From Harvey P. Dale, Apr 23 2011 *)
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PROG
| (PARI) A152075(n)={ local( p=prime(n), q=p); until( issquarefree(q-p), q=nextprime(q+1)); q} [From M. F. Hasler (www.univ-ag.fr/~mhasler), Nov 23 2008]
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CROSSREFS
| Cf. A152076.
Sequence in context: A143245 A018205 A121047 * A092789 A092793 A024909
Adjacent sequences: A152072 A152073 A152074 * A152076 A152077 A152078
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Nov 23 2008
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EXTENSIONS
| Terms beyond a(13) from M. F. Hasler (www.univ-ag.fr/~mhasler) and Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 23 2008
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