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%I #11 Oct 15 2013 22:31:25
%S 4,9,16,1225,6036849,10909809,29484900,326561041,653058025,952833424,
%T 10487398464
%N Square composite numbers with square subscripts.
%C a(12) > 5*10^11. [From _Donovan Johnson_, Feb 06 2010]
%F Solutions to c[x^2]=y^2: the values of y^2; where c(j)=j-th composite number; See program.
%e composite=1225=35.35=A002808(1024)=c(32.32).
%t c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] Do[s=c[n^2]; If[IntegerQ[Sqrt[s]], Print[s]], {n, 1, 1000000}]
%Y Cf. A002808, A073171, A073172.
%K nonn
%O 1,1
%A _Labos Elemer_, Jul 19 2002
%E a(10)-a(11) from _Donovan Johnson_, Feb 06 2010
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