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 A137626 The largest prime in the first set of n consecutive primes for which p+4 is semiprime. 3
 5, 31, 181, 733, 1777, 8363, 8369, 19273, 175333, 175349, 33952819 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = last prime in the first run of n primes such that p+4 is semiprime for each prime p in the run. [Sean A. Irvine, Feb 13, 2012.] LINKS EXAMPLE a(2)=31 is the largest in a set of 2 consecutive primes {29,31}, and 29+4=33=3*11 and 31+4=35=5*7 are both semiprime.  No smaller number has this property. 59 is not in the sequence because although 47+4=51=3*17 and 53+4=57=3*19 are both semiprime, 59+4=63=3*3*7 is not. CROSSREFS Cf. A001358 A137625 A137627 A137628. Sequence in context: A034353 A180635 A078526 * A202753 A057426 A015540 Adjacent sequences:  A137623 A137624 A137625 * A137627 A137628 A137629 KEYWORD more,nonn AUTHOR Enoch Haga, Jan 30 2008 EXTENSIONS a(11) from Sean A. Irvine, Feb 12 2012 STATUS approved

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