[seqfan] Smallest palindromic prime by adding at least one digit to each the left and right of n

[Felix Fröhlich]

Hello SeqFans,

The sequence defined in the title of the thread starts 101, 313, 727, 131,
11411, 151, 10601, 373, 181, 191, 31013, 1114111, 1212121, 11311, 11411,
31513, 1616161, 1117111, 1218121 ....

This is a bit like A090287. Computing terms of A090287 should be relatively
easy, I guess. But how can this sequence be effectively computed? One could
start by adding '1' to the left and right of n and then increase the right
digit. How long does the right digit need to be incremented until the left
one needs to be incremented (and the right digit be reset to 1)? I just
don't see right now what algorithm could be applied for computing the terms.

Best regards
Felix