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A068138
Primes in the mirror concatenation of primes without reversal.
0
2, 131175323571113, 19171311753235711131719
OFFSET
1,1
COMMENTS
No further terms < 10^1000. - Andrew Howroyd, Sep 19 2024
EXAMPLE
323 is not a prime hence not a member but concatenation of primes up to 13 about 2 i.e. 131175323571113 is a prime and a term.
MATHEMATICA
Select[Table[FromDigits[Flatten[IntegerDigits/@Join[Prime[Range[n, 1, -1]], Prime[Range[2, n]]]]], {n, 8}], PrimeQ] (* Harvey P. Dale, Mar 14 2021 *)
PROG
(PARI) b(n)={my(v=[digits(p)|p<-primes(n)]); fromdigits(concat(vector(2*n-1, k, v[1+abs(n-k)])))}
{ select(isprime, vector(100, n, b(n))) } \\ Andrew Howroyd, Sep 19 2024
CROSSREFS
Sequence in context: A007352 A257229 A176944 * A309968 A082566 A273400
KEYWORD
base,nonn,bref
AUTHOR
Amarnath Murthy, Feb 22 2002
EXTENSIONS
Offset changed by Andrew Howroyd, Sep 19 2024
STATUS
approved