OFFSET
1,1
EXAMPLE
1103 belongs to this sequence because 10*1103 + k and k*10^4 + 1103, for k = 1 to 9, are all composite.
MATHEMATICA
fQ[n_] := Block[{e = Floor[ Log10@ n] + 1, r = Range@ 9}, Union@ Flatten[ PrimeQ[{10 n + r, r*10^e + n}]] == {False}]; Select[ Prime@ Range@ 1550, fQ] (* Robert G. Wilson v, Apr 15 2014 *)
PROG
(PARI) for(n=2, 12983, v=n; if(isprime(n), s=#Str(v); t=0; for(k=1, 9, if(isprime(10*v+k)||isprime(k*10^s+v), break, t++)); if(t==9, print1(v, ", "))); n=v);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Arkadiusz Wesolowski, Apr 13 2014
STATUS
approved