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A061465 a(n) = floor(Sum_{k=1..n} sqrt(2k-1)). 1

%I

%S 1,2,4,7,10,13,17,21,25,29,34,39,44,49,54,60,66,72,78,84,90,97,104,

%T 110,117,125,132,139,147,155,162,170,178,186,195,203,212,220,229,238,

%U 247,256,265,275,284,294,303,313,323,333,343,353,363,374,384,395,405,416

%N a(n) = floor(Sum_{k=1..n} sqrt(2k-1)).

%H Harry J. Smith, <a href="/A061465/b061465.txt">Table of n, a(n) for n = 1..1000</a>

%e a(3) = floor(sqrt(1) + sqrt(3) + sqrt(5)) = floor(4.96811878506866...) = 4. [corrected by _Clark Kimberling_, Jan 14 2011]

%t Floor[Accumulate[Sqrt[2Range[60]-1]]] (* _Harvey P. Dale_, Feb 09 2014 *)

%o (PARI) { default(realprecision, 100); for (n=1, 1000, write("b061465.txt", n, " ", floor(sum(k=1, n, sqrt(2*k - 1)))) ) } \\ _Harry J. Smith_, Jul 23 2009

%K easy,nonn

%O 1,2

%A _Jason Earls_, Jun 10 2001

%E Corrected description and more terms from Larry Reeves (larryr(AT)acm.org), Jun 12 2001

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Last modified October 26 08:00 EDT 2021. Contains 348267 sequences. (Running on oeis4.)