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

Author

Jon Perry, Nov 04 2012

Keywords

• nonn

Crossrefs

Cf. A000604, A181788.

Programs

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)
				

Formula

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