The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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. 2
 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 Adjacent sequences: A064429 A064430 A064431 * A064433 A064434 A064435 KEYWORD nonn AUTHOR Don Reble, Oct 17 2001 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 27 13:15 EST 2023. Contains 359840 sequences. (Running on oeis4.)