31419

Appears in sequences

• a(n) = 1 - 2*n^2 + 4*n*(1 + 2*n^2)/3.at n=23A168547
• Number of 1..8 integer arrays v[1..n] of length n with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..n-1.at n=4A171282
• Number of 1..n integer arrays v[1..5] of length 5 with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..4.at n=7A171342
• Number of nX7 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.at n=3A208839
• T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.at n=48A208840
• Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.at n=6A208841
• Number of (w,x,y,z) with all terms in {1,...,n} and w <= harmonic mean of {x,y,z}.at n=17A212104
• Number of surviving even nodes at generation n in the binary tree of persistently squarefree numbers (see A293230).at n=37A293518
• Expansion of Sum_{k>=0} x^(k*(k+1)) / Product_{j=1..k} (1 - j*x^j).at n=32A306663
• Number of regions in a polygon whose boundary consists of n+2 equally spaced points around the arc of a semicircle. See Comments for precise definition.at n=28A333643
• Number of conjugacy classes of subgroups of the group GL(2, Z_n) of invertible 2 X 2 matrices mod n.at n=29A364921