18064

Appears in sequences

• a(n) = (117*n^2 - 99*n + 2)/2.at n=18A050408
• McKay-Thompson series of class 40A for Monster.at n=50A058662
• Difference between larger and smaller terms of n-th amicable pair.at n=20A066539
• Half the number of nX4 binary arrays with no element equal to a strict majority of its horizontal and vertical neighbors.at n=8A183305
• Half the number of nX9 binary arrays with no element equal to a strict majority of its horizontal and vertical neighbors.at n=3A183310
• Number of arrangements of 3 nonzero numbers x(i) in -n..n with the sum of trunc(x(i)/x(i+1)) equal to zero.at n=22A189546
• Numbers n such that n!3 - 3^3 is prime, where n!3 = n!!! is a triple factorial number (A007661).at n=26A247463
• Number of rooted highly irregular trees with n nodes.at n=31A259863
• Numbers missing from A001033 despite satisfying the necessary congruence conditions (see comments).at n=25A274470
• Difference between the larger and smaller terms of the n-th amicable pair (x,y) given in A259933.at n=20A275469
• Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) + 1, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=43A294869
• Expansion of 1 / (chi(-x) * chi(-x^3)) in powers of x where chi() is a Ramanujan theta function.at n=49A328798
• Let t_k denote the triangular number k*(k+1)/2. Suppose 0 < x < y < z are integers satisfying t_x + t_y = t_p, t_y + t_z = t_q, t_x + t_z = t_r, for integers p,q,r. Sort the triples [x,y,z] first by x, then by y. Sequence gives the values of q.at n=46A332592
• Number of different multisets that can be obtained by choosing a prime index (or a prime factor) of each integer from 2 to n.at n=43A355746