OFFSET
1,1
COMMENTS
C1 = 'prevprime(k) followed by k'.
C2 = 'k followed by prevprime(k)'.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1000
EXAMPLE
n=747 -> previous prime is 743, thus '743747' and '747743' are both primes.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Oct 15 1998
EXTENSIONS
Offset changed by Andrew Howroyd, Aug 13 2024
STATUS
approved