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A133758 Total number of restricted left truncatable primes in base n. 0
0, 3, 5, 4, 149, 7, 144, 37, 1442 (list; graph; refs; listen; history; text; internal format)
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), p. 254-264.

LINKS

Table of n, a(n) for n=2..10.

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.

Sequence in context: A167808 A161353 A182045 * A242288 A021742 A284867

Adjacent sequences:  A133755 A133756 A133757 * A133759 A133760 A133761

KEYWORD

nonn

AUTHOR

Martin Renner, Jan 04 2008

STATUS

approved

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Last modified February 21 01:03 EST 2019. Contains 320362 sequences. (Running on oeis4.)