

A097970


Numbers n such that 7*10^n + 3 is prime.


2



1, 4, 6, 16, 22, 39, 103, 163, 240, 1048, 1974, 2559, 5880, 14436, 28338, 32796, 38079, 56779, 91215, 111325, 115863, 138604
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OFFSET

1,2


COMMENTS



LINKS



FORMULA



EXAMPLE

For n = 1 we have 7*10^1+3 =7*10+3 = 73, which is prime.


MATHEMATICA

Do[ If[ PrimeQ[ 7*10^n + 3], Print[ n ]], {n, 0, 10000}] (* Robert G. Wilson v, Jan 19 2005 *)
Flatten[Position[Table[7 10^n+3, {n, 100000}], _?PrimeQ]] (* Harvey P. Dale, Nov 01 2011 *)


PROG

(PARI) main(m)=select(n>isprime(7*10^n + 3), vector(m, i, i)) \\ Anders Hellström, Aug 15 2015


CROSSREFS



KEYWORD

more,nonn


AUTHOR

Julien Peter Benney (jpbenney(AT)ftml.net), Sep 07 2004


EXTENSIONS



STATUS

approved



