19416

Appears in sequences

• Coordination sequence for hexagonal close-packing.at n=43A007899
• Theta series of 8-d 6-modular lattice G_2 tensor F_4 (or A_2 tensor D_4) with det 1296 and minimal norm 4 in powers of q^2.at n=12A028977
• Becomes prime after n iterations of f(x) = sigma(x)-1 (least inverse of A039655).at n=19A039656
• Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,5.at n=31A064239
• Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,45.at n=9A064259
• Inverse binomial transform of [0, A133474].at n=19A139797
• a(n) = 1728*n - 1320.at n=11A157263
• Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2>2x^2+2y^2.at n=27A211633
• Number of -3..3 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having two, three, four, six, seven or eight distinct values for every i,j,k<=n.at n=4A211760
• Number of n X 3 binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.at n=5A268990
• T(n,k)=Number of nXk binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.at n=33A268995
• Number of 6Xn binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.at n=2A269000
• Numbers k such that k - 13, k + 1, k + 5, k + 7, and k + 13 are all prime.at n=7A281937
• Numbers n such that A002088(n) < 3n^2/Pi^2.at n=36A285022
• Expansion of 1 / Sum_{k>=0} (-x)^(k*(3*k - 1)/2).at n=40A308806
• Numbers k such that the largest unitary divisor of sigma(k) that is coprime with A003961(k) is also a unitary divisor of k.at n=49A351551
• Number of winning positions for the next player (a, b, c) where 1 <= a, b, c <= n in "Divisor Nim" (see comments).at n=29A383226