-340

Appears in sequences

• Expansion of e.g.f.: sech(arctan(x)+log(x+1))=1-4/2!*x^2+6/3!*x^3+77/4!*x^4-340/5!*x^5...at n=5A012971
• Expansion of e.g.f.: sech(tanh(x)+log(x+1))=1-4/2!*x^2+6/3!*x^3+77/4!*x^4-340/5!*x^5...at n=5A013128
• Discriminants of quadratic number fields Q(sqrt -n) for n squarefree.at n=52A033197
• McKay-Thompson series of class 18C for the Monster group.at n=21A058533
• Expansion of (1-x)/(1+x+2*x^2).at n=20A078050
• Triangle reads by rows: T(n,k) = coefficient of x^k in (x^3-2*x^2-2*x+1)^n.at n=42A078692
• Triangle reads by rows: T(n,k) = coefficient of x^k in (x^3-2*x^2-2*x+1)^n.at n=41A078692
• Expansion of q^(-1/24) (m (1-m) / 16)^(1/24) in powers of q, where m = k^2 is the parameter and q is the nome for Jacobian elliptic functions.at n=31A081360
• a(n) = -a(n-1) + 2*a(n-2), a(0)=1, a(1)=2.at n=10A084247
• Expansion of (1+x-4*x^2) / ((1+x)*(1-4*x^2)).at n=10A087213
• Sum_{k=1..2*n-1} J(4*n,k)*k, where J(i,j) is the Jacobi symbol.at n=58A097542
• McKay-Thompson series of class 18C for the Monster group with a(0) = -3.at n=21A123676
• Triangle T(n,0)=0 and T(n,k) = -A028421(n-1,k-1), 0<k<=n.at n=25A136426
• Riordan array ((1+x^2)/(1-x)^2, -x/(1-x)^2).at n=56A136672
• Triangle T(n,k) read by rows: coefficient [x^k] of the polynomial p(n,x) with p(0,x) = 1, p(1,x) = 2 - x, p(2,x) = 1 - 4*x + x^2 and p(n,x) = (2-x)*p(n-1,x) - p(n-2,x) if n>2.at n=41A136674
• Triangle read by rows, T[n,2i-1]=2T[n-1,i],T[n,2i]=2k-1-2T[n-1,i].at n=43A138583
• Triangle T(d,n) read by rows, the n-th term of the d-th differences of the Jacobsthal sequence A001045.at n=47A140503
• Triangle by rows with row n formed by coefficients of the characteristic polynomial of the n X n tridiagonal matrix with m_{i,i} = 2 for i=1..n, m_{i,i-1} = m_{i,i+1} = -1 for i=2..n-1, and m_{1,2} = m_{n,n-1} = -2.at n=41A140882
• Triangle T(n,k) read by rows, the k-th term of the n-th differences of the Jacobsthal sequence A001045.at n=57A140944
• Sum of termwise product of mu(k) and reduced residue system k mod n.at n=53A143729