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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

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Last modified December 7 06:16 EST 2022. Contains 358649 sequences. (Running on oeis4.)