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%I #5 Dec 05 2013 19:56:51
%S 0,41,7,0,2,449,645751,82842712474619,0,162277,3,
%T 464101615137754587054892683011,605551,7,
%U 87298334620741688517926539978239961,0,1231,2,3,47,5
%N Smallest prime formed by the digit string after decimal point of n^(1/2), or 0 if no such prime exists.
%C Conjecture: a(n) is nonzero if n is not a perfect square.
%C For n=22, no provable primes were found with fewer than 256 digits. - _Wouter Meeussen_, Jun 04 2004
%e a(7) = 645751 as 7^(1/2) = 2.64575131106459059... and the least prime is 645751.
%t << NumberTheory`PrimeQ`; it = Table[{n, k = 1; While[temp = Floor[10^k FractionalPart[n^(1/2)]]; k < 256 && (temp === 1 || ! ProvablePrimeQ[temp]), k++ ]; temp, k}, {n, 2, 21}]
%K base,nonn
%O 1,2
%A _Amarnath Murthy_, Jun 02 2004
%E Corrected and extended by _Wouter Meeussen_, Jun 04 2004
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