OFFSET
1,3
COMMENTS
Least squared radius of a circle around a grid point of the square lattice such that the number of grid points on this circle is not smaller than the number of grid points on any circle around a grid point of the square lattice with smaller radius. a(1) = 0 by convention.
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..440
PROG
(PARI) r2=0; for(k=0, 6000, my(a004018 = if( k<1, k==0, 4 * sumdiv( k, d, (d%4==1) - (d%4==3)))); if(a004018>=r2, r2=a004018; print1(k, ", ")))
(Julia) using Nemo
function A326311List(len)
R, x = PolynomialRing(ZZ, "x")
e = theta_qexp(2, len, x)
L = [coeff(e, j) for j in 0:len - 1]
m = ZZ(0)
[n - 1 for (n, l) in enumerate(L) if l == (m = max(m, l))]
end
A326311List(1000) |> println # Peter Luschny, Sep 12 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Sep 11 2019
STATUS
approved