OFFSET
1,1
COMMENTS
This is unsorted, and in order of appearance of emirps.
All values are multiples of 18 (A008600). - Charles R Greathouse IV, Oct 15 2012
EXAMPLE
a(1) = absolute value of first emirp versus its reversal = |13 - 31| = |-18| = 18.
a(2) = |17 - 71| = |-54| = 54.
a(3) = |31 - 13| = |18| = 18.
a(4) = |37 - 73| = |-36| = 36.
MAPLE
R:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||n):
q:= n-> isprime(n) and (p-> p<>n and isprime(p))(R(n)):
map(x-> abs(x-R(x)), select(q, [$2..1280]))[]; # Alois P. Heinz, Jul 12 2024
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Jonathan Vos Post, Oct 07 2012
EXTENSIONS
Corrected and more terms from Georg Fischer, Jul 12 2024
STATUS
approved