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A067267 Numbers n such that n, 10*n+1, 10*n+3, 10*n+7 and 10*n+9 are all primes. 8
19, 6949, 10111, 15727, 20149, 24799, 26041, 26881, 29587, 29947, 40213, 41203, 44257, 46747, 47701, 49057, 50023, 51061, 55921, 66109, 66643, 73939, 76819, 79579, 95947, 106501, 110083, 111781, 112213, 114679 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
All terms == 1 (mod 6). - Robert Israel, Jan 22 2018
LINKS
EXAMPLE
a(1)=19 because 191, 193, 197 and 199 are all prime.
MAPLE
select(t -> andmap(isprime, [t, 10*t+1, 10*t+3, 10*t+7, 10*t+9]), [seq(i, i=1..2*10^5, 6)]); # Robert Israel, Jan 22 2018
MATHEMATICA
okQ[n_]:=Module[{n10=10n}, And@@PrimeQ[{n10+1, n10+3, n10+7, n10+9}]]
Select[Prime[Range[20000]], okQ] (* Harvey P. Dale, Dec 13 2010 *)
Select[Prime[Range[11000]], AllTrue[10#+{1, 3, 7, 9}, PrimeQ]&] (* Harvey P. Dale, Feb 23 2022 *)
CROSSREFS
Cf. A007811.
Sequence in context: A172662 A201303 A013724 * A340165 A124989 A265964
KEYWORD
nonn
AUTHOR
Sudipta Das (juitech(AT)vsnl.net), Feb 21 2002
STATUS
approved

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Last modified April 22 12:48 EDT 2024. Contains 371900 sequences. (Running on oeis4.)