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 A087055 Largest square number less than 2*n^2. 6

%I

%S 1,4,16,25,49,64,81,121,144,196,225,256,324,361,441,484,576,625,676,

%T 784,841,961,1024,1089,1225,1296,1444,1521,1681,1764,1849,2025,2116,

%U 2304,2401,2500,2704,2809,3025,3136,3249,3481,3600,3844,3969,4225,4356,4489

%N Largest square number less than 2*n^2.

%H Michael De Vlieger, <a href="/A087055/b087055.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A001951(n)^2 = floor(n*sqrt(2))^2.

%e a(10) = 196 because 196 is the largest square less than 2*10^2 = 200.

%t Table[Floor[Sqrt[2n^2-1]],{n,100}]^2 (* _Harvey P. Dale_, Mar 26 2011 *)

%o (PARI) a(n) = sqrtint(2*n^2)^2; \\ _Michel Marcus_, Jul 08 2020

%Y Cf. A000290, A001951, A087056, A087057, A087058, A087059, A087060.

%K easy,nonn

%O 1,2

%A _Jens Voß_, Aug 07 2003

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Last modified September 29 06:29 EDT 2020. Contains 337425 sequences. (Running on oeis4.)