OFFSET
0,7
LINKS
FORMULA
a(n) = |floor(sqrt(n) + 1/2)^2 - n|. - Ridouane Oudra, May 01 2019
a(n) <= sqrt(n). - Charles R Greathouse IV, Nov 16 2022
EXAMPLE
a(7)=2 since 9 is the closest square to 7 and |9-7| = 2.
MATHEMATICA
Flatten[Table[Abs[Nearest[Range[0, 25]^2, n]-n], {n, 0, 120}]] (* Harvey P. Dale, Mar 14 2011 *)
PROG
(Haskell)
a053188 0 = 0
a053188 n = min (n - last xs) (head ys - n) where
(xs, ys) = span (< n) a000290_list
-- Reinhard Zumkeller, Nov 28 2011
(Python)
from math import isqrt
def A053188(n): return abs(((m:=isqrt(n))+int(n-m*(m+1)>=1))**2-n) # Chai Wah Wu, Aug 03 2022
(PARI) a(n)=abs(((sqrtint(4*n) + 1)\2)^2 - n) \\ Charles R Greathouse IV, Nov 16 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Henry Bottomley, Mar 01 2000
STATUS
approved