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%I #15 Sep 06 2015 14:15:04
%S 17,13,5,181,587,13,163,2,13789,1013,163,653,11,3931,397,2039,439,
%T 4447,1217,269,1733,3,5,2239,197,3,1061,14563,1901,3,149,359,2137,67,
%U 433,11,907,2339,673,19181,11593,89,6883,3,28571,997,43,3559,2287,1931,911
%N Smallest prime in a sequence of n consecutive primes which add to a perfect square.
%C Essentially the same as A073887.
%H Zak Seidov, <a href="/A132955/b132955.txt">Table of n, a(n) for n = 2..1000</a>
%F a(n)={ min prime(k): [ sum(j=k..k+n-1) prime(j)] in A000290}. - _R. J. Mathar_, Nov 27 2007
%e a(2)=17, because it is the smallest prime in a sequence of n=2 consecutive primes, which add to a perfect square, namely 17+19=36=6^2. The sums of earlier pairs, 2+3, 3+5, 5+7, 7+11 etc. fail to produces sums which are any perfect square.
%t Module[{prs=Prime[Range[3200]]},Table[First[SelectFirst[Partition[ prs, n,1],IntegerQ[ Sqrt[Total[#]]]&]],{n,2,52}]] (* The program uses the SelectFirst function from Mathematica version 10 *) (* _Harvey P. Dale_, Sep 06 2015 *)
%o (PARI) a(n) = {ip = 1; while (! issquare(sum(i=ip, ip+n-1, prime(i))), ip++); prime(ip);} \\ _Michel Marcus_, Jun 08 2014
%Y Cf. A132956, A132957.
%K easy,nonn
%O 2,1
%A _Enoch Haga_, Sep 06 2007
%E Edited by _R. J. Mathar_, Nov 27 2007
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