Problems & Puzzles: Puzzles

Puzzle 51.- Pi such that Pi is Palprime & i = palindrome

Apart from the first 4 trivial ones:

P2 = 3
P
3 = 5
P
4 = 7
P
5 = 11

I have found the first non trivial:

P8114118 = 143787341

(See the Sloane’s sequences A046941 and A046942)

a) Can you find the following non-trivial of such Pi’s?
b) Can you find the first Pi (non-trivial) such that both Pi and i are palprimes, (if they exist)?

Solution

Felice Russo wrote (17/06/99) "I didn't find any further solution up to i = 120768111"

***

Giovanni Resta got (May 2003) the next solution to question a):

Here it is the next number which is a palindromic prime with a palindromic index: 11853735811 is the 535,252,535-th prime. (a nice number by itself)

***

Giovanni Resta got (Aug 2019) the next solution to question a):

p(4025062605204) =  126537757735621.

(See the Sloane’s sequences A046941 and A046942)

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