21524

Appears in sequences

• Coordination sequence for MgNi2, Position Mg2.at n=36A009935
• Number of partitions of n in which the number of parts divides n.at n=49A067538
• a(n) equals the (n*(n+1)/2)-th partial sum of the self-convolution cube of A010054, which has the g.f.: Sum_{k>=0} x^(k*(k+1)/2).at n=34A109414
• a(n) = n^3/6 + 3*n^2/4 + 7*n/3 + 7/8 + (-1)^n/8.at n=49A173154
• Partial sums of Sum_{k=1..n} n/gcd(n,k), or partial sums of Sum_{d|n} d*phi(d) (see A057660).at n=43A174405
• Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, up, down.at n=2A177643
• A sequence related to Le Corbusier's Modulor: round(phi^(-13 + n)*175).at n=23A227572
• Number of (n+2) X (2+2) 0..1 arrays with every 2 X 2 and 3X3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically.at n=17A253504
• Triangle read by rows: T(n,k) = number of nonequivalent dissections of an n-gon into k polygons by nonintersecting diagonals up to rotation and reflection.at n=61A295634
• Number of length-n binary strings having a string attractor of size at most 2.at n=20A355520
• Triangular array T(n,k), read by rows: coefficients of strong divisibility sequence of polynomials p(1,x) = 1, p(2,x) = 1 + 3*x, p(n,x) = u*p(n-1,x) + v*p(n-2,x) for n >= 3, where u = p(2,x), v = 3 - x^2.at n=42A368152