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 A174858 Primes p of a prime triplet (p,p+2,p+6) with property that concatenation p//(p+2)//(p+6) is prime. 1
 5, 11, 17, 41, 11171, 16061, 16187, 20897, 29021, 34841, 36011, 39227, 41177, 51341, 55331, 56891, 58907, 63311, 64151, 69191, 77261, 82757, 113021, 122027, 123731, 135461, 151337, 167621, 173291, 174761, 187631, 191447, 195731, 203207 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS If p is a d-digit prime of a triple: p*10^(2*d) + (p+2)*10^d + p+6 = (10^(2*d)+10^d+1) * p + 2*(10^d+3) to be a prime No such concatenation for a 4-digit p: d=4, p*10^8 + (p+2)*10^4 + p+6 = = p*(10^8 + 10^4 + 1) + 2*10^4 + 6, coefficients (10^8 + 10^4 + 1) and 2*(10^4 + 3) have both divisor 7 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE (5,7,11) is 1st prime triplet, 5711 = prime(752), 5 is 1st term of sequence (11,13,17) is 2nd prime triplet, 111317 = prime(10561), 11 is 2nd term of sequence MATHEMATICA Transpose[Select[Partition[Prime[Range[20000]], 3, 1], Differences[#]=={2, 4} && PrimeQ[ FromDigits[Flatten[IntegerDigits/@#]]]&]][[1]] (* Harvey P. Dale, Apr 10 2013 *) CROSSREFS Sequence in context: A172454 A162001 A171713 * A095183 A018730 A050836 Adjacent sequences:  A174855 A174856 A174857 * A174859 A174860 A174861 KEYWORD base,nonn,uned AUTHOR Ulrich Krug (leuchtfeuer37(AT)gmx.de), Mar 31 2010 STATUS approved

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