OFFSET

1,1

COMMENTS

In a general base b, a number qualifies as a member iff: (i) it is a prime, (ii) when its digits in base b are reversed, it is still a prime, and (iii) when, in base b, it has more than one digit and the least significant one is dropped, the remaining prefix has the same properties. This implies that any base-b prefix of such a number, no matter how many right-side digits are truncated, is still a right-truncatable reversible prime. Sequences of this type appear to be all finite (see A238854, A238855, and A238856, used as examples).

This particular sequence is for base b = 10.

See also A238854 for comments on a more general context.

LINKS

Stanislav Sykora, PARI/GP scripts for genetic threads, with code and comments.

EXAMPLE

739 is a member because it is a prime and so is 937, as well as the pair (73, 37) and 7.

PROG

(PARI) See the link.

CROSSREFS

KEYWORD

nonn,fini,full,base,easy,changed

AUTHOR

Stanislav Sykora, Mar 06 2014

STATUS

approved