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.

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

Offset: 0

Author

Don Reble, Oct 17 2001

Keywords

• nonn

Examples

			a(1) = 2 because 19, 17, 13 and 11 are all prime.
		

Links

• Sean A. Irvine, Table of n, a(n) for n = 0..50

Crossrefs

Cf. A064281.

Programs

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 *)