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A102723 Smallest prime a(n) such that a(n)-x and a(n)+x, for x=1 to n, are all composite. 1
5, 23, 23, 53, 53, 211, 211, 211, 211, 211, 211, 1847, 1847, 2179, 2179, 2179, 2179, 3967, 3967, 16033, 16033, 16033, 16033, 24281, 24281, 24281, 24281, 24281, 24281, 38501, 38501, 38501, 38501, 38501, 38501, 38501, 38501, 38501, 38501, 58831 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(2n+1)=a(2n). - Robert G. Wilson v, Feb 22 2005

LINKS

Table of n, a(n) for n=1..40.

MATHEMATICA

f[n_] := Block[{k = 1}, While[ Union[ PrimeQ /@ Sort[ Flatten[ Table[{Prime[k] - i, Prime[k] + i}, {i, n}]]]] != {False}, k++ ]; Prime[k]]; Table[ f[n], {n, 40}] (* Robert G. Wilson v, Feb 22 2005 *)

CROSSREFS

Cf. A023186.

Sequence in context: A177242 A233756 A002582 * A136146 A167804 A196243

Adjacent sequences:  A102720 A102721 A102722 * A102724 A102725 A102726

KEYWORD

nonn

AUTHOR

Ray G. Opao, Feb 06 2005

EXTENSIONS

a(12)-a(40) from Robert G. Wilson v, Feb 22 2005

STATUS

approved

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Last modified December 2 21:35 EST 2016. Contains 278694 sequences.