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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A108113 Numbers k such that the string 3137k is prime. 1
 9, 11, 17, 21, 27, 39, 41, 63, 77, 83, 117, 137, 143, 159, 171, 179, 201, 209, 243, 257, 263, 311, 357, 371, 389, 399, 447, 461, 471, 507, 509, 513, 521, 531, 551, 567, 569, 573, 593, 609, 611, 623, 627, 663, 669, 681, 699, 723, 731, 747, 749, 777, 803, 837 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 31 and 37 are primes. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE If k=9, then 3137k = 31379 (prime). If k=83, then 3137k = 313783 (prime). MAPLE a:=proc(n) local z: z:=nops(convert(n, base, 10)): if isprime(3137*10^z+n)=true then n else fi end: seq(a(n), n=1..1000); # Emeric Deutsch, Jul 02 2005 MATHEMATICA Select[Range[900], PrimeQ[3137*10^IntegerLength[#]+#]&] (* Harvey P. Dale, Mar 19 2015 *) PROG (Magma) [ n: n in [1..900] | IsPrime(Seqint(Intseq(n) cat [7, 3, 1, 3])) ]; // Vincenzo Librandi, Feb 03 2011 CROSSREFS Sequence in context: A048464 A075824 A228951 * A111391 A077788 A339048 Adjacent sequences: A108110 A108111 A108112 * A108114 A108115 A108116 KEYWORD nonn,base AUTHOR Parthasarathy Nambi, Jun 25 2005 EXTENSIONS More terms from Emeric Deutsch, Jul 02 2005 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 28 11:30 EST 2023. Contains 359860 sequences. (Running on oeis4.)