25844

Appears in sequences

• Number of 4-line partitions of n (i.e., planar partitions of n with at most 4 lines).at n=19A002799
• Numbers k such that usigma(k) = phi(k)*omega(k), where omega(k) is the number of distinct prime divisors of k.at n=18A063795
• Composite numbers k such that sigma(k)*(phi(k) + 2) is a square.at n=34A065655
• G.f.: Product_{n >= 0} (1+x^(2n+1))/(1-x^(2n+1)).at n=43A080054
• Series expansion for radius of gyration of osculating polygons on square lattice.at n=6A121770
• Nearest integer to the space diagonal of the smallest (measured by the longest edge) primitive (gcd(a,b,c)=1) Euler bricks (a, b, c, sqrt(a^2 + b^2), sqrt(b^2 + c^2), sqrt(a^2 + c^2) are integers). If the space diagonal is an integer then the Euler brick is called a "perfect cuboid". There are no known perfect cuboids.at n=27A141029
• Records in A071786.at n=44A151766
• Expansion of phi(-q) / phi(q^2) in powers of q where phi() is a Ramanujan theta function.at n=43A210030
• Larger of amicable pair m < n defined by t(n) = m and t(m) = n where t(n) = psi(n) - n and psi(n) = A001615(n) is the Dedekind psi function.at n=14A323330
• Number of parts, counted without multiplicity, in all compositions of n.at n=14A336875