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%I #14 May 17 2017 03:17:38
%S 1,1,2,1,2,2,1,2,2,2,1,3,2,3,1,2,2,2,2,3,1,2,2,2,3,2,2,2,3,2,2,2,2,2,
%T 2,2,3,2,3,2,3,3,2,2,2,2,2,3,1,3,3,2,2,2,2,2,3,2,3,2,2,2,2,2,2,2,1,2,
%U 2,2,2,3
%N a(n) is the number of different prime divisors of A214723(n).
%C The records of a(n) are a(1)=1, a(3)=2, a(12)=3, a(132)=4,... Is the sequence unbounded?
%H G. C. Greubel, <a href="/A215113/b215113.txt">Table of n, a(n) for n = 1..5000</a>
%F a(n) = A001221(A214723(n)). - _Michel Marcus_, Feb 08 2016
%t nn = 2000; ps = Prime[Range[PrimePi[Sqrt[nn]]]]; t = Flatten[Table[ ps[[i]]^2 + ps[[j]]^2, {i, Length[ps]}, {j, i, Length[ps]}]]; t =
%t Select[t, # <= nn &]; PrimeNu[Sort[Transpose[Select[Tally[t], #[[2]] == 1 &]][[1]]]] (* _G. C. Greubel_, May 16 2017 *)
%Y Cf. A001221, A214723.
%K nonn
%O 1,3
%A _Vladimir Shevelev_, Aug 03 2012
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