21744

Appears in sequences

• If there were a 9-dimensional unimodular lattice with minimal norm 2, this would be its theta series; however, no such lattice exists.at n=8A032800
• Expansion of (1+2*x+3*x^2)/((1-x)^3*(1-x^2)).at n=34A055232
• a(n) = (sum of digits of n)^4 - (sum of digits^4 of n).at n=49A069964
• Number of 4 X n (0,1) matrices such that each row and each column is nondecreasing or nonincreasing.at n=11A086114
• a(n) = 2^n for n = 0..4; for n > 4, a(n) = 2*a(n-1) + a(n-5).at n=14A098588
• Riordan array ((1-x)/(1-3*x), x*(1-x)/(1-3*x)).at n=48A125693
• a(1)=1, a(n) = a(n-1) + n^5 if n odd, a(n) = a(n-1) + n^4 if n is even.at n=6A135214
• Number of binary arrays indicating the locations of trailing edge maxima of a random length-n 0..2 array extended with zeros and convolved with 1,2,2,1.at n=25A222105
• Number of (7+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.at n=15A250661
• Numbers k such that 97*10^k - 3 is prime.at n=22A281111
• Detour index of the n X n grid graph.at n=5A296779
• Detour index of the n X n knight graph.at n=2A296781
• Detour index for the n X n torus grid graph.at n=3A296784
• Maximum detour index of any bipartite graph on n nodes.at n=35A296819
• Expansion of ( Sum_{k>=0} k^2 * q^(k^2) )^4.at n=39A347803
• a(n) = Sum_{k=3..n} binomial(k,3) * floor(n/k).at n=26A366971