|
| |
|
|
A049735
|
|
Array T(i,j) is the number of lattice points (x,y) in circle with radius (0,0)-to-(i,j), read by antidiagonals.
|
|
10
|
|
|
|
1, 5, 5, 13, 9, 13, 29, 21, 21, 29, 49, 37, 25, 37, 49, 81, 57, 45, 45, 57, 81, 113, 89, 69, 61, 69, 89, 113, 149, 121, 97, 81, 81, 97, 121, 149, 197, 161, 129, 109, 101, 109, 129, 161, 197, 253, 213, 177, 145, 137, 137, 145, 177, 213, 253
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
COMMENTS
|
Specifically, x^2 + y^2 <= i^2 + j^2.
|
|
|
LINKS
|
Table of n, a(n) for n=0..54.
|
|
|
FORMULA
|
T(n,0) = A000328(n).
|
|
|
EXAMPLE
|
Antidiagonals (each starting on row 0):
{1},
{5, 5},
{13, 9, 13},
...
Array begins:
1 5 13 29 49 81
5 9 21 37 57 89
13 21 25 45 69 97
29 37 45 61 81 109
49 57 69 81 101 137
81 89 97 109 137 161
|
|
|
PROG
|
(PARI) T(n, k) = my(z=norml2([n, k]), m=ceil(sqrt(2)*max(n, k))); sum(x=-m, m, sum(y=-m, m, norml2([x, y]) <= z)); \\ Michel Marcus, Aug 07 2021
|
|
|
CROSSREFS
|
Cf. A000328 (1st column or row).
Sequence in context: A206553 A122213 A224067 * A055526 A146984 A055524
Adjacent sequences: A049732 A049733 A049734 * A049736 A049737 A049738
|
|
|
KEYWORD
|
nonn,tabl
|
|
|
AUTHOR
|
Clark Kimberling
|
|
|
STATUS
|
approved
|
| |
|
|
