OFFSET
1,3
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..2000
EXAMPLE
All substrings and reversal substrings of 186 are nonprimes: 1, 6, 8, 18, 68, 81, 86, 186, 681.
MATHEMATICA
Select[Range[0, 1000], NoneTrue[Union[Flatten[{#, IntegerReverse[#]}&/@Flatten[Table[ FromDigits/@Partition[IntegerDigits[#], d, 1], {d, IntegerLength[#]}]]]], PrimeQ]&] (* Harvey P. Dale, Jul 30 2024 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Dec 25 2011
EXTENSIONS
Corrected (498 deleted) by Harvey P. Dale, Jul 30 2024
STATUS
approved