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A064432 Least k such that k*10^n-9, k*10^n-7, k*10^n-3 and k*10^n-1 are all prime. 3
14, 2, 2, 248, 1856, 7190, 719, 15308, 13415, 18434, 13532, 26975, 6935, 61763, 17786, 60140, 6014, 297974, 103199, 56321, 80009, 428186, 303476, 32558, 1361063, 444275, 634451, 116573, 303593, 293822, 1068491, 651464, 1855937, 3217754, 364985, 569129 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
EXAMPLE
a(1) = 2 because 19, 17, 13 and 11 are all prime.
MATHEMATICA
Do[k = 1; While[ !PrimeQ[k*10^n - 1] || !PrimeQ[k*10^n - 3] || !PrimeQ[k*10^n - 7] || !PrimeQ[k*10^n - 9], k++ ]; Print[k], {n, 0, 35} ] (* Robert G. Wilson v *)
CROSSREFS
Cf. A064281.
Sequence in context: A040191 A040193 A064972 * A040194 A107834 A070701
KEYWORD
nonn
AUTHOR
Don Reble, Oct 17 2001
STATUS
approved

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Last modified July 18 18:59 EDT 2024. Contains 374388 sequences. (Running on oeis4.)