20680

Appears in sequences

• The difference between the largest part and the smallest part summed over all those partitions of n in which every integer from the smallest part to the largest part occurs.at n=50A117471
• E.g.f. A(x) = G(x)^2/x where G(x) satisfies: G(G(x))^2 = G(x)^2 * G'(x) and G(x) is the g.f. of A179499.at n=4A179499
• E.g.f. A(x) satisfies: A( cos(x) - exp(-x) ) = x.at n=5A205806
• Triangle of coefficients of polynomials u(n,x) jointly generated with A209696; see the Formula section.at n=52A209695
• Column 0 of square array A211970 (in which column 1 is A000041).at n=29A211971
• a(n) is the number of terms in the expansion of (x-y)(x^3-y^3)*(x^6-y^6)*(x^10-y^10)*...*(x^T_i-y^T_i), where T_i is the i-th triangular number.at n=48A222028
• Numbers m = concat(s,t) such that m = (sigma(s)-s) * (sigma(t)-t), where sigma(x)-x is the sum of the aliquot parts of x.at n=1A253825
• Partial sums of the Dedekind psi_2(k) function, for 1 <= k <= n.at n=37A321973
• a(n) = Sum_{k=0..n} BellPolynomial(n, k), row sums of A350263.at n=5A350264
• Number of regions formed inside a right triangle by the straight line segments mutually connecting all vertices and points on the two shorter edges whose positions on one edge equal the Farey series of order n while on the other they divide its length into n equal segments.at n=9A359975
• Number of 4-cycles in the n-Pell graph.at n=9A364619