2,2

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.

Angell, I. O. and Godwin, H. J. "On Truncatable Primes." Math. Comput. 31, 265-267, 1977.

Steven Kahan; Sol Weintraub: Left truncatable primes. In: Journal of recreational mathematics 29 (1998), p. 254-264.

Index entries for sequences related to truncatable primes

Eric Weisstein: Truncatable Prime.

Cf. A076623, A055521.

Sequence in context: A078439 A007063 A127397 this_sequence A021742 A138112 A106233

Adjacent sequences: A133755 A133756 A133757 this_sequence A133759 A133760 A133761

nonn

Martin Renner (martin.renner(AT)gmx.net), Jan 04 2008