A380371 a(n) is the integer part of the area of a rhombus with side n and angle n degrees.

0, 0, 0, 0, 1, 2, 3, 5, 8, 12, 17, 23, 29, 38, 47, 58, 70, 84, 100, 117, 136, 158, 181, 206, 234, 264, 296, 330, 368, 407, 450, 494, 542, 593, 646, 702, 761, 823, 889, 957, 1028, 1102, 1180, 1261, 1344, 1431, 1522, 1615, 1712, 1812, 1915, 2021, 2130, 2243, 2359

Offset

0,6

Comments

The angle n ranges 0 to 180 inclusive.

Terms increase to a maximum 12951 at n = 131 and then decrease.

Links

Nicolay Avilov, Table of n, a(n) for n = 0..180

Formula

a(n) = floor(n^2*sin(Pi*n/180)).

Example

a(30) = 30*30*sin(30 degrees) = 450.
a(90) = 8100 is the area of a square with a side of 90.

Crossrefs

Sequence in context: A104664 A338921 A333343 * A022856 A089071 A177205

Adjacent sequences: A380368 A380369 A380370 * A380372 A380373 A380374

Keyword

nonn,easy,fini,full

Author

Nicolay Avilov, Jan 23 2025

Status

approved