login
A260874
Smallest prime of the form p//r//p//r//p//r// ...., where p = prime(n), r = A004086(p) and // denotes concatenation.
1
1331133113, 17711771177117711771177117711771177117711771177117711771177117711771177117, 19911991199119, 23322332233223322332233223322332233223322332233223322332233223322332233223322332233223322332233223322332233223322332233223, 2992299229, 31133113311331
OFFSET
6,1
LINKS
PROG
(PARI) a(n) = p=prime(n); r=eval(concat(Vecrev(Str(p)))); s=eval(Str(p, r)); i=0; while(!ispseudoprime(s), if(i%2==0, s=eval(Str(s, p)); i++, s=eval(Str(s, r)); i++)); s
CROSSREFS
Sequence in context: A172787 A172849 A213161 * A251358 A346959 A068746
KEYWORD
nonn,base
AUTHOR
Felix Fröhlich, Aug 02 2015
STATUS
approved