OFFSET
2,2
COMMENTS
Prime digits p in base n are counted if there is no prime with 2 digits which can have its leftmost digit removed to produce p; e.g., in base 10 the prime digits 2 and 5 are counted, because there are no primes containing them as rightmost digit.
REFERENCES
Steven Kahan; Sol Weintraub: Left truncatable primes. In: Journal of recreational mathematics 29 (1998), pp. 254-264.
LINKS
I. O. Angell and H. J. Godwin, On Truncatable Primes, Math. Comput. 31, 265-267, 1977.
Eric Weisstein's World of Mathematics, Truncatable Prime
Chai Wah Wu, On a conjecture regarding primality of numbers constructed from prepending and appending identical digits, arXiv:1503.08883 [math.NT], 2015.
CROSSREFS
KEYWORD
nonn
AUTHOR
Martin Renner, Jan 04 2008
STATUS
approved