A046949 Sizes of successive balls in D_4 lattice.

1, 25, 49, 145, 169, 313, 409, 601, 625, 937, 1081, 1369, 1465, 1801, 1993, 2569, 2593, 3025, 3337, 3817, 3961, 4729, 5017, 5593, 5689, 6433, 6769, 7729, 7921, 8641, 9217, 9985, 10009, 11161, 11593, 12745, 13057, 13969, 14449, 15793, 15937, 16945, 17713, 18769

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Index entries for sequences related to D_4 lattice

Formula

a(n) ~ Pi^2 * n^2. - Vaclav Kotesovec, Jan 14 2024

Mathematica

A004011 = Join[{1}, Table[24*Sum[d*Mod[d, 2], {d, Divisors[n]}], {n, 1, 40}]]; Accumulate[A004011](* Jean-François Alcover, Apr 25 2012 *)

Prog

(PARI) B=1; bl=[ 1 ]; for (n=1, 200, t1=divisors(2*n); t2=0; for (i=1, length(t1), if( t1[ i ]%4 <> 0, t2=t2+t1[ i ])); B=B+8*t2; bl=concat(bl, B)); bl

Crossrefs

Partial sums of A004011.

Sequence in context: A131706 A110015 A110586 * A137659 A020325 A108604

Adjacent sequences: A046946 A046947 A046948 * A046950 A046951 A046952

Keyword

nonn

Author

N. J. A. Sloane

Status

approved