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 A105145 Numbers n such that the string n10001 is prime. 1
 18, 21, 30, 32, 39, 71, 72, 78, 84, 86, 89, 93, 95, 98, 107, 108, 135, 143, 150, 152, 159, 161, 165, 170, 173, 177, 179, 180, 192, 198, 203, 221, 243, 245, 248, 261, 269, 281, 282, 294, 302, 306, 315, 320, 329, 336, 338, 347, 369, 374, 378, 395, 399, 423, 425, 443, 446, 449, 456, 458, 471, 500, 504 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE If n=18, then n10001 = 1810001 (prime). If n=98, then n10001 = 9810001 (prime). MAPLE read("transforms") : for n from 1 to 1000 do p := digcat2(n, 10001) ; if isprime(p) then printf("%d, ", n); end if; end do: # R. J. Mathar, Feb 02 2011 MATHEMATICA Select[Range[600], PrimeQ[#*10^5+10001]&] (* Harvey P. Dale, Apr 29 2018 *) CROSSREFS Cf. A105106, A105107. Sequence in context: A172052 A001101 A088341 * A244603 A120416 A293751 Adjacent sequences:  A105142 A105143 A105144 * A105146 A105147 A105148 KEYWORD base,nonn,easy AUTHOR Parthasarathy Nambi, Apr 09 2005 STATUS approved

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Last modified June 4 06:41 EDT 2020. Contains 334822 sequences. (Running on oeis4.)