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%I #5 Jul 18 2012 19:56:04
%S 1,7,2,1,2,5,838,232,121,8,151,202,2,101,646,5,1,151,424,404,242,131,
%T 646,272,16361,1,494,1,868,101,494,12421,14041,151,595,383,515,19091,
%U 10001,242,17171,20602,161,292,11011,8,1,11611,22822,232,17771,616,767
%N Consider all (2n+1)-digit palindromic primes of the form 90...0M0...09 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M.
%H Vincenzo Librandi, <a href="/A100957/b100957.txt">Table of n, a(n) for n = 1..200</a>
%t f[n_] := Block[{k = 0, t = Flatten[ Join[{9}, 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, 55}]
%Y Cf. A100026, A100955, A100956.
%K base,nonn
%O 1,2
%A _Robert G. Wilson v_, Nov 23 2004
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