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

1,2

Links

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

Example

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

Mathematica

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

Prog

(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

Crossrefs

Sequence in context: A287420 A003067 A130243 * A368784 A126022 A194172

Adjacent sequences: A061462 A061463 A061464 * A061466 A061467 A061468

Keyword

easy,nonn

Author

Jason Earls, Jun 10 2001

Extensions

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

Status

approved