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 A186142 a(n) is the smallest suffix such that the numbers with k digits "9" prepended are primes for k = 1, 2, ...,n. 1
 7, 7, 29, 907, 32207, 573217, 3136717, 4128253 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A186143 for the digit "3" case. The corresponding sequences with the digits "1" or "7" are not possible because if Xn and XXn are prime, then XXXn will be a multiple of 3 when X is 1 or 7. LINKS EXAMPLE a(3) = 29 because 329, 3329, 33329 are primes. MATHEMATICA m=1; Table[While[d=IntegerDigits[m]; k=0; While[k++; PrependTo[d, 9]; k <= n && PrimeQ[FromDigits[d]]]; k <= n, m++]; m, {n, 6}] CROSSREFS Cf. A186069, A186070. Sequence in context: A198341 A299338 A246039 * A188274 A255281 A255283 Adjacent sequences:  A186139 A186140 A186141 * A186143 A186144 A186145 KEYWORD nonn,base AUTHOR Michel Lagneau, Feb 13 2011 STATUS approved

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Last modified September 20 12:34 EDT 2019. Contains 327235 sequences. (Running on oeis4.)