-675

Appears in sequences

• Related to discordant permutations.at n=7A002633
• McKay-Thompson series of class 5B for the Monster group with a(0) = 0.at n=16A007252
• a(n) = -(1/2)*(n+2)*(n^2 - 6*n - 1).at n=13A028494
• McKay-Thompson series of class 5B for the Monster group with a(0) = 1.at n=16A045483
• Determinant of the n X n tridiagonal matrix M with the elements on the diagonals equal to 1, except M(n,n-1)=M(n-1,n)=n.at n=24A080322
• McKay-Thompson series of class 5B for the Monster group with a(0) = -6.at n=16A106248
• a(2n) = A001570(n), a(2n+1) = -A007654(n+1).at n=5A108946
• a(n)=the (1,2)-entry of the n-th power of the 2 X 2 matrix [0,-1;n-1,3*(n-1)].at n=3A109521
• Semiprime(n)*semiprime(n+3) - semiprime(n+1)*semiprime(n+2), where semiprime(n) is the n-th semiprime.at n=41A118780
• a(n) = -a(n-6) + 3*a(n-5) + a(n-4) - 7*a(n-3) + a(n-2) + 3*a(n-1).at n=12A122504
• a(n) = (-1)^n*n*(n-2).at n=26A131386
• a(2*n) = 1-n^2, a(2*n+1) = n*(n+1).at n=50A131723
• Triangle T(n,0)=0 and T(n,k) = -A028421(n-1,k-1), 0<k<=n.at n=24A136426
• Expansion of (1-5*x-x^2+x^3)/((1+x)*(1-x)^3).at n=25A141354
• A symmetrical triangle sequence: T(n, k) = q^k + q^(n-k) - q^n, with q=3.at n=24A176225
• Triangle T(n,k), n>=0, 0<=k<=2n, read by rows: row n gives the coefficients of the chromatic polynomial of the complete bipartite graph K_(n,n), highest powers first.at n=23A212084
• Discriminant of the pure cubic field Q(m^(1/3)), where m = A004709(n) is the n-th cubefree number.at n=4A242867
• Discriminant of the pure cubic field Q(m^(1/3)), where m = A004709(n) is the n-th cubefree number.at n=21A242867
• Triangle read by rows: coefficients T(n,k) of a binomial decomposition of 2^n-1 as Sum(k=0..n)T(n,k)*binomial(n,k).at n=25A244124
• Triangle read by rows: terms T(n,k) of a binomial decomposition of 2^n-1 as Sum(k=0..n)T(n,k).at n=19A244125