The number of triangular lattice points whose Euclidean distance from the origin is less than or equal to n.
A308685
The number of triangular lattice points whose Euclidean distance from the origin is less than or equal to n.
Terms
- a(0) =1a(1) =7a(2) =19a(3) =37a(4) =61a(5) =91a(6) =127a(7) =187a(8) =241a(9) =301a(10) =367a(11) =439a(12) =517a(13) =613a(14) =721a(15) =823a(16) =931a(17) =1045a(18) =1165a(19) =1303a(20) =1459a(21) =1615a(22) =1765a(23) =1921a(24) =2083a(25) =2263a(26) =2455a(27) =2653a(28) =2857a(29) =3055
External references
- oeis: A308685