A344471 Number of points in the hexagonal lattice A_2 on the circle centered at the origin with squared radius A230655(n).

1, 6, 12, 18, 24, 36, 48, 54, 72, 96, 108, 144, 192, 216, 288, 384, 432, 576, 648, 768, 864, 960, 1152, 1296, 1536, 1728, 1920, 2304, 2592, 3072, 3456, 3840, 4608, 5184, 6144, 6912, 7680, 9216, 10368, 12288, 13824, 15360, 18432, 20736, 23040, 24576, 27648

Offset

1,2

Comments

Record values of A004016.

Links

Jianing Song, Table of n, a(n) for n = 1..247

Formula

a(n) = A004016(A230655(n)).

a(n) = 6*A000005(A230655(n)) = 6*A002324(A230655(n)), n > 1.

Example

24 is a term because the circle with radius sqrt(91) centered at the origin hits exactly 24 points in the A_2 lattice, and any circle with radius < sqrt(91) centered at the origin hits fewer than 24 points.

Prog

(PARI) my(v=list_A344473(10^15), rec=0); print1(1, ", "); for(n=1, #v, if(numdiv(v[n])>rec, rec=numdiv(v[n]); print1(6*rec, ", "))) \\ see program for A344473

Crossrefs

Cf. A230655, A004016, A002324, A344472, A000005, A344473.

Cf. A071385 (similar sequence).

Sequence in context: A215142 A033845 A187778 * A120942 A147306 A359957

Adjacent sequences: A344468 A344469 A344470 * A344472 A344473 A344474

Keyword

nonn

Author

Jianing Song, May 20 2021

Status

approved