Problems & Puzzles: Puzzles

Puzzle 518. Pi=prime(Pi-1) Farideh Firoozbakht poses the following puzzle: Let P1, P2, ... Pk be EMIRPS defined by the following recursive definition: Pi=prime(Pi-1), i=2 to k .............(*) Pi+1 is not EMIRP where, as usual, prime(1)=2, prime(2)=3, ... The following are the least P1 EMIRPS for k=1 to 4: 13, 37, 167 & 1471. For example: 1471 generates by (*) the following 4 EMIRPS: 1471, 12301, 131707 & 1751411 Q. Find the least P1 EMIRPS for K>4.

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