A066643 a(n) = floor(Pi*n^2).

0, 3, 12, 28, 50, 78, 113, 153, 201, 254, 314, 380, 452, 530, 615, 706, 804, 907, 1017, 1134, 1256, 1385, 1520, 1661, 1809, 1963, 2123, 2290, 2463, 2642, 2827, 3019, 3216, 3421, 3631, 3848, 4071, 4300, 4536, 4778, 5026, 5281, 5541, 5808, 6082, 6361, 6647

Offset: 0

Author

Amarnath Murthy, Dec 29 2001

Keywords

• easy
• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A338020 (first differences).

Programs

Mathematica

Table[ Floor[Pi*n^2], {n, 1, 50} ]

PARI

{ for (n=1, 1000, write("b066643.txt", n, " ", floor(Pi*n^2)) ) } \\ Harry J. Smith, Mar 15 2010

Formula

a(n) = floor(Pi*n^2).

a(n) = A022844(n^2) . - R. J. Mathar, Jan 25 2023

Extensions

Corrected and extended by Robert G. Wilson v, Jan 03 2002