69121

Appears in sequences

• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (-1, 1, 1), (0, -1, 1), (0, 1, -1), (1, 0, 0)}.at n=10A148712
• Positive numbers y such that y^2 is of the form x^2+(x+409)^2 with integer x.at n=10A160577
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+239)^2 = y^2.at n=11A204765
• 21*n^4 - 36*n^3 + 25*n^2 - 8*n + 1.at n=8A239426
• Composite numbers k such that b^k == b (mod sigma(k)) for every integer b.at n=3A277286
• L.g.f.: -log( Sum_{n=-oo..+oo} (-2)^n * (2*x)^(n^2) ) = Sum_{n>=1} a(n) * x^n/n.at n=7A337950
• Number of regions among all distinct circles that can be constructed from n equally spaced points along a line using only a compass.at n=22A359253
• Integers k such that k^2 can be written as the sum of three positive fourth powers.at n=14A365657
• Primitive solutions k to k^2 = u^4 + v^4 + w^4, with u, v, w > 0.at n=4A365688