A394301 a(n) is the number of unit squares in the square lattice, divided by 4, that have 1 vertex strictly inside and 3 vertices strictly outside the circle (x-1/2)^2 + (y-1/2)^2 = n, i.e., the circle centered at the deep hole.

0, 1, 1, 2, 2, 1, 1, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 2, 2, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 6, 6, 6, 6, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 5, 5, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7, 6

Offset

0,4

Links

Hugo Pfoertner, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A005883, A393697, A394302, A394303.

Sequence in context: A102481 A231201 A348841 * A394305 A295515 A348890

Adjacent sequences: A394298 A394299 A394300 * A394302 A394303 A394304

Keyword

nonn

Author

Hugo Pfoertner, Mar 15 2026

Status

approved