A355761 a(n) is the number of grid points in a square lattice strictly outside of the area enclosed by n loops of an Archimedean spiral and inside (or on the boundary) of a circle with radius n.
0, 3, 5, 8, 9, 17, 16, 17, 19, 25, 35, 27, 26, 37, 39, 49, 41, 46, 47, 53, 62, 51, 66, 63, 57, 76, 77, 85, 75, 77, 87, 79, 93, 92, 100, 112, 93, 106, 97, 122, 125, 107, 115, 115, 131, 138, 123, 130, 126, 134, 147, 164, 163, 149, 151, 148, 171, 159, 172, 160, 172, 180, 176
Offset: 0
Keywords
Examples
See the PDF in links.
Links
- Karl-Heinz Hofmann, Examples of a(1..8)
- Wikipedia, Archimedean spiral