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, 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

Offset

1,1

Comments

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

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Mathematica

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

Prog

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

Crossrefs

Cf. A152076.

Sequence in context: A018205 A370762 A121047 * A092789 A092793 A361977

Adjacent sequences: A152072 A152073 A152074 * A152076 A152077 A152078

Keyword

nonn

Author

Leroy Quet, Nov 23 2008

Extensions

Terms beyond a(13) from M. F. Hasler and Ray Chandler, Nov 23 2008

Status

approved