21047

Appears in sequences

• Number of paraffins C_n H_{2n-1} X_3 with n carbon atoms.at n=11A000641
• a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 3, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n-1 <= 2^(p+1), with a(1) = a(2) = 1.at n=17A049884
• 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), (0, 1, 1), (1, 0, 0)}.at n=8A150195