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Largest square <= 2^n.
2

%I #15 Dec 13 2024 12:38:53

%S 1,4,4,16,25,64,121,256,484,1024,2025,4096,8100,16384,32761,65536,

%T 131044,262144,524176,1048576,2096704,4194304,8386816,16777216,

%U 33547264,67108864,134212225,268435456,536848900,1073741824,2147395600,4294967296,8589767761,17179869184

%N Largest square <= 2^n.

%H Harry J. Smith, <a href="/A065732/b065732.txt">Table of n, a(n) for n = 1..200</a>

%F a(n) = A048760(A000079(n)) = A048760(2^n).

%t Table[Floor[Sqrt[2^w]//N]^2, {w, 1, 50}]

%o (PARI) a(n) = { sqrtint(2^n)^2 } \\ _Harry J. Smith_, Oct 28 2009

%Y Cf. A048760, A000079, A065730-A065741.

%K easy,nonn

%O 1,2

%A _Labos Elemer_, Nov 15 2001