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

1, 2, 4, 7, 10, 13, 17, 21, 25, 29, 34, 39, 44, 49, 54, 60, 66, 72, 78, 84, 90, 97, 104, 110, 117, 125, 132, 139, 147, 155, 162, 170, 178, 186, 195, 203, 212, 220, 229, 238, 247, 256, 265, 275, 284, 294, 303, 313, 323, 333, 343, 353, 363, 374, 384, 395, 405, 416

Offset: 1

Author

Jason Earls, Jun 10 2001

Keywords

• easy
• nonn

Examples

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

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Programs

Mathematica

Floor[Accumulate[Sqrt[2Range[60]-1]]] (* Harvey P. Dale, Feb 09 2014 *)

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

Extensions

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