20803

Appears in sequences

• Number of 3 X 3 integer matrices with elements in the range [ -n,n ] which generate a group of order two under binary matrix multiplication.at n=8A054466
• Counterbalanced numbers: Composite numbers k such that phi(k)/(sigma(k)-k) is an integer.at n=22A055940
• Numbers k such that phi(k) = sigma(phi(phi(k))).at n=8A115448
• Numbers k such that (k-1)*2^k + 1 is prime.at n=11A128001
• 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, -1, 0), (-1, 0, -1), (0, 0, 1), (1, -1, 1), (1, 1, 0)}.at n=8A150189
• Numbers which do not reach zero under either of the iterations: x -> floor(sqrt(x)) * (x - floor(sqrt(x))^2) or y -> ceiling(sqrt(y)) * (ceiling(sqrt(y))^2 - y).at n=25A219963
• Number of 4 X n 0..1 arrays with diagonals and antidiagonals unimodal and rows nondecreasing.at n=14A223951
• Index sequence for limit-reversing A000002; see Comments.at n=46A245937
• Number of simple graphs on n nodes with vertex count > edge count + 1.at n=12A333865
• Numbers k such that 3^k*k^3 + 2 is a prime.at n=12A366997