OFFSET
1,2
COMMENTS
Is this the same as "Longest palindromic proper substring of A100027(n) or A028989(n+1) that occurs only once in the decimal representation of A100027(n) or A028989(n+1), respectively"? - Felix Fröhlich, Apr 30 2022
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..1000
MATHEMATICA
f[n_] := Block[{k = 0, t = Flatten[Join[{1}, Table[0, {n - 1}]]]}, While[s = Drop[t, Min[ -Floor[ Log[10, k]/2], 0]]; k != FromDigits[ Reverse[ IntegerDigits[k]]] || !PrimeQ[ FromDigits[ Join[s, IntegerDigits[k], Reverse[s]]]], k++ ]; k]; Table[ f[n], {n, 56}] (* Robert G. Wilson v, Nov 22 2004 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Harvey Dubner (harvey(AT)dubner.com), Nov 20 2004
EXTENSIONS
More terms from Robert G. Wilson v, Nov 22 2004
STATUS
approved