A333462 a(n) is the number of Gaussian integers z such that (n-1)/2 < |z| <= n/2, divided by 4.

0, 1, 1, 1, 2, 2, 2, 3, 5, 3, 4, 4, 6, 3, 7, 5, 7, 7, 10, 6, 8, 7, 11, 5, 12, 10, 12, 9, 13, 11, 10, 12, 16, 10, 18, 9, 19, 11, 18, 14, 14, 15, 21, 15, 20, 14, 22, 13, 23, 19, 23, 17, 24, 18, 22, 19, 27, 17, 26, 22, 28, 17, 31, 21, 26, 24, 28, 26, 30, 27, 29, 21

Offset

1,5

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

Prog

(PARI) c=vectorsmall(2000000); for(x=1, 1000, my(x2=x*x); c[x2]++; c[x2+x2]++; for(y=1, x-1, my(y2=y*y); c[x2+y2]+=2));
a(n)=sum(k=ceil((1+(n-1)^2)/4), floor(n^2/4), c[k]);
for(k=1, 72, print1(a(k), ", "))

Crossrefs

Cf. A004018, A232705, A333572, A333573.

Sequence in context: A276824 A235998 A303949 * A133850 A160902 A082408

Adjacent sequences: A333459 A333460 A333461 * A333463 A333464 A333465

Keyword

nonn

Author

Hugo Pfoertner, Mar 26 2020

Status

approved