OFFSET
0,2
LINKS
FORMULA
EXAMPLE
a(10^2) = 660, a(10^3) = 6392, a(10^4) = 62952, a(10^5) = 628520, a(10^6) = 6281404. - Reinhard Zumkeller, Jan 13 2002
PROG
(Magma)
[#[<x, y>: x in [-n..n], y in [-n..n]| n-1 lt r and r le n where r is Sqrt(x^2+ y^2)]: n in [0..50]]; // Marius A. Burtea, Feb 18 2020
(Sage)
def A036693(n):
if n == 0: return 1
Range = lambda n: ((i, j) for i in (-n..n) for j in (-n..n))
return sum(1 for (j, k) in Range(n) if (n-1)^2 < j^2 + k^2 <= n^2)
print([A036693(n) for n in range(20)]) # Peter Luschny, Mar 27 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved