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A239789
Primes which are a concatenation of prime(k), prime(k+2) and prime(k+4) for some k.
2
172331, 233141, 717989, 137149157, 191197211, 197211227, 223229239, 229239251, 257269277, 331347353, 353367379, 359373383, 467487499, 521541557, 617631643, 619641647, 647659673, 677691709, 733743757, 787809821, 797811823, 103310491061, 106110691091, 109711091123
OFFSET
1,1
LINKS
EXAMPLE
172331 is a prime and appears in the sequence because it is the concatenation of prime(7), prime(7+2) and prime(7+4).
233141 is a prime and appears in the sequence because it is the concatenation of prime(9), prime(9+2) and prime(9+4).
MAPLE
with(StringTools): KD := proc() local a, b, d, e; a:=ithprime(n); b:=ithprime(n+2); d:=ithprime(n+4);
e:= parse(cat(a, b, d)); if isprime(e) then RETURN (e); fi; end: seq(KD(), n=1..500);
MATHEMATICA
Select[Table[FromDigits[Flatten[{IntegerDigits[Prime[n]], IntegerDigits[Prime[n+2]], IntegerDigits[Prime[n+4]]}]], {n, 1, 500}], PrimeQ]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
K. D. Bajpai, Mar 26 2014
STATUS
approved