A218711 Number of nonnegative solutions to x^2 + y^2 + z^2 < n^2.

0, 1, 8, 23, 51, 90, 157, 230, 341, 471, 639, 835, 1063, 1340, 1671, 2022, 2443, 2893, 3428, 4004, 4653, 5359, 6133, 6977, 7907, 8886, 9991, 11152, 12428, 13724, 15192, 16683, 18358, 20072, 21932, 23880, 25941, 28117, 30397, 32822, 35376, 38013, 40840, 43765, 46880, 50090, 53448, 56911, 60583, 64379

Offset

0,3

Links

Table of n, a(n) for n=0..49.

Formula

a(n) = A000604(n) - A181788(n).

Prog

(JavaScript)
for (i=0; i<50; i++) {
d=0;
for (a=0; a<=i; a++)
for (b=0; b<=i; b++)
for (c=0; c<=i; c++)
if (Math.pow(a, 2)+Math.pow(b, 2)+Math.pow(c, 2)<Math.pow(i, 2)) d++;
document.write(d+", ");
}

Crossrefs

Cf. A000604, A181788.

Sequence in context: A212118 A175346 A225280 * A270694 A027054 A358246

Adjacent sequences: A218708 A218709 A218710 * A218712 A218713 A218714

Keyword

nonn

Author

Jon Perry, Nov 04 2012

Status

approved