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

0,1

Links

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

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

Adjacent sequences: A064429 A064430 A064431 * A064433 A064434 A064435

Keyword

nonn

Author

Don Reble, Oct 17 2001

Status

approved