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%I #15 Jul 29 2013 11:21:38
%S 2,50,50,60,70,6,2,7600,47,5,4,93,6,34,5,9600,71,4,74,320,3,372,13,
%T 846,32,9600,339,9765,202,3,69,6,9900,13,8586,9600,4,46,3,4,446,3,
%U 9900,4,1256,614,819,3365,8,36400,76,647,35,39548,9900,4740
%N Smallest k > 1 such that k^n has k as its middle digits, or 0 if no such k exists.
%C Is a(88) the first 0? If a(88) is nonzero, it is greater than 2 * 10^8. - _T. D. Noe_, Jul 29 2013
%e a(6) = 6 because 6^6 = 46656 has 6 as its middle digit.
%t Table[k = 2; While[c0 = IntegerDigits[k]; c1 = IntegerDigits[k^n]; len0 = Length[c0]; len1 = Length[c1]; f = (len1 - len0)/2; ! (OddQ[len0] == OddQ[len1] && c0 == Take[c1, {f + 1, f + len0}]), k++]; k, {n, 56}] (* _T. D. Noe_, Jul 29 2013 *)
%Y Cf. A062118.
%K nonn,base
%O 1,1
%A _Michel Lagneau_, Jul 27 2013
%E Corrected by _T. D. Noe_, Jul 29 2013
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