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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 August 10 02:28 EDT 2020. Contains 336367 sequences. (Running on oeis4.)