|
|
A108107
|
|
Numbers n such that the string 1123n is the decimal expansion of a prime number.
|
|
0
|
|
|
9, 27, 31, 37, 39, 49, 61, 63, 97, 127, 151, 181, 189, 211, 217, 219, 231, 247, 267, 279, 303, 307, 319, 327, 349, 351, 361, 379, 391, 399, 403, 427, 429, 439, 477, 483, 487, 501, 511, 517, 531, 541, 553, 561, 567, 589, 597, 601, 621, 631, 637, 651, 667
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
11 and 23 are primes.
|
|
LINKS
|
|
|
EXAMPLE
|
9 is in the sequence because 11239 is prime.
63 is in the sequence because 112363 is prime.
127 is in the sequence because 1123127 is prime.
|
|
MAPLE
|
a:=proc(n) local z: z:=nops(convert(n, base, 10)): if isprime(1123*10^z+n)=true then n else fi end: seq(a(n), n=1..750); # Emeric Deutsch, Jul 02 2005
|
|
PROG
|
(Magma) [ n: n in [1..700] | IsPrime(Seqint(Intseq(n) cat [3, 2, 1, 1])) ];
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|