|
%I #8 Mar 21 2013 10:05:55
%S 2357,3571,5711,3137,7717,8389,1103,1031,7109,1091,911,2713,9151,1511,
%T 1571,3167,9181,1811,1193,1931,9319,9719,1223,7229,3323,9241,7127,
%U 1277,1283,8329,3307,1733,7331,3313,3373,7349,3533,3359,3593,3673,6737,3733
%N Take A000040, omit commas: 23571113171923..., select 4-digit primes seen when scanning from left.
%e In the sequence 2357111317192329... (primes without delimiters) 4-digit primes are: 2357, 3571, 5711, 3137, 7717, ...
%t p200=Flatten[IntegerDigits[Prime[Range[200]]]]; n=4; (* n-digit primes!*) pn=Partition[p200, n, 1]; ln=Length[pn]; tab=Table[Sum[10^(n-k)*pn[[i, k]], {k, n}], {i, ln}]; Select[tab, PrimeQ]
%t FromDigits/@Select[Partition[Flatten[IntegerDigits[Prime[Range[100]]]],4,1], PrimeQ[FromDigits[#]]&] (* _Harvey P. Dale_, Mar 21 2013 *)
%K easy,nonn,base
%O 1,1
%A _Zak Seidov_, Aug 22 2002
|
