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A085720
Start of a run of 7 successive numbers which when concatenated form a prime.
1
7, 37, 157, 185, 187, 271, 301, 355, 475, 485, 523, 533, 577, 611, 653, 661, 667, 731, 733, 755, 761, 791, 853, 911, 913, 937, 983, 1085, 1111, 1187, 1205, 1253, 1397, 1417, 1585, 1631, 1655, 1685, 1697, 1711, 1723, 1841, 1907, 1975, 2035, 2077, 2105, 2185
OFFSET
1,1
COMMENTS
Concatenation of three and six successive numbers are always composite.
Primes as concatenation of two, four and five successive numbers are in A030458, A030471, A052087, A052088, A052089.
LINKS
MATHEMATICA
f[n_] := FromDigits[ Flatten[ Table[ IntegerDigits[i], {i, n, n + 6}]]]; Select[ Range[2190], PrimeQ[ f[ # ]] & ]
Select[Range[2500], PrimeQ[FromDigits[Flatten[IntegerDigits/@Range[#, #+6]]]]&] (* Harvey P. Dale, Aug 15 2021 *)
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Zak Seidov, Jun 27 2003
EXTENSIONS
Edited by Robert G. Wilson v, Jun 28 2003
Edited by Charles R Greathouse IV, Apr 24 2010
STATUS
approved