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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 (list; graph; refs; listen; history; text; internal format)
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

Harvey P. Dale, Table of n, a(n) for n = 1..1000

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

Cf. A030458, A030471, A052087, A052088, A052089.

Sequence in context: A202119 A201083 A036678 * A201962 A269257 A269258

Adjacent sequences: A085717 A085718 A085719 * A085721 A085722 A085723

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

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Last modified January 28 14:10 EST 2023. Contains 359895 sequences. (Running on oeis4.)