22368

Appears in sequences

• Number of Greek-key tours on a 3 X n board; i.e., self-avoiding walks on a 3 X n grid starting in the top left corner.at n=13A046994
• Open 3-dimensional ball numbers (version 3): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (1/2,1/2,0).at n=35A053595
• Rectangular table, read by antidiagonals, where the g.f. of row n, R(x,n), satisfies: R(x,n) = 1 + (n+1)*x*R(x,n+1)^2 for n>=0.at n=26A128570
• Row 1 of table A128570.at n=5A128571
• Triangle T, read by rows, where column k of T = column 0 of T^(k+1) for k>0, with column 0 of T = column 0 of T^4 shift right.at n=30A138271
• Column 2 of triangle A138271; also, column 0 of matrix power A138271^3.at n=5A138274
• (Number of permutations of {1,2,...,n} for which sums of three consecutive numbers (with wraparound) are all distinct)/2n.at n=6A206477
• Triangle of coefficients of polynomials v(n,x) jointly generated with A208759; see the Formula section.at n=51A208760
• Number of squares of all sizes in polyominoes obtained by union of two pyramidal figures (A092498) with intersection equals A002623.at n=39A260918
• Number of maximal matchings in the n X n rook graph.at n=3A289198
• Totients t such that the number of divisors of t equals the number of solutions of phi(x) = t.at n=21A305058
• G.f.: exp( Sum_{n>=1} A322201(n)*x^n/n ), where A322201(n) is the coefficient of x^n*y^n/(2*n) in Sum_{n>=1} -log(1 - (x^n + y^n)).at n=9A322202
• Array read by antidiagonals: T(n,m) is the number of maximal matchings in the rook graph K_n X K_m.at n=40A341847
• Number of maximal matchings in the 4 X n rook graph.at n=4A341849
• a(n) = Sum_{k=1..n} k * rad(k).at n=43A350996
• Expansion of g.f. f/(1+2*f) where f is the g.f. of nonempty permutations.at n=8A355488
• Triangle read by rows. The partition transform of A355488, which are the alternating row sums of the number of permutations of [n] with k components (A059438).at n=37A357078