A049474 a(n) = ceiling(n/sqrt(2)).

0, 1, 2, 3, 3, 4, 5, 5, 6, 7, 8, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 15, 16, 17, 17, 18, 19, 20, 20, 21, 22, 22, 23, 24, 25, 25, 26, 27, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 34, 35, 36, 37, 37, 38, 39, 39, 40, 41, 42, 42, 43, 44, 44, 45, 46, 46, 47

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Crossrefs

A099188(n) = 2*a(n).

Cf. A049472.

Programs

Haskell

a049474 = ceiling . (/ sqrt 2) . fromIntegral
-- Reinhard Zumkeller, Jul 01 2015

Mathematica

Table[Ceiling[n/Sqrt[2]], {n,0,50}] (* G. C. Greubel, Jul 06 2017 *)

PARI

a(n)=if(n,sqrtint((n^2-1)\2)+1,0) \\ Charles R Greathouse IV, Sep 02 2015