A133758 Total number of restricted left truncatable primes in base n.

0, 3, 5, 4, 149, 7, 144, 37, 1442

Offset: 2

Author

Martin Renner, Jan 04 2008

Keywords

• nonn

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.
• Index entries for sequences related to truncatable primes

Crossrefs

Cf. A076623, A055521.