-1848

Appears in sequences

• Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^8 in powers of x.at n=33A001486
• a(n) = Sum_{d|n, d == 1 mod 4} d^2 - Sum_{d|n, d == 3 mod 4} d^2.at n=42A002173
• Expansion of e.g.f.: cosh(x)/exp(tan(x)).at n=7A009186
• Expansion of sin(tanh(x))*cos(x).at n=3A009523
• Expansion of (1-4*x)^(13/2).at n=13A020925
• Dirichlet inverse of the Jordan function J_2 (A007434).at n=42A046970
• McKay-Thompson series of class 10b for Monster.at n=38A058103
• McKay-Thompson series of class 15D for the Monster group.at n=56A058511
• Sum_{d divides n} d^2*(-1)^bigomega(d), where bigomega(n) = A001222(n).at n=42A076792
• Signed array used for numerators of generating functions of the column sequences of array A090452.at n=30A091029
• Triangle T(n,k) read by rows: consider the sequence a(m) = a(m-1) + sum_{0<j<=m/n} a(m-j*n) with a(0)=1. Row n of T(n,k) is formed by the coefficients of the recurrence relation of sequence b(i) = a(n*i).at n=41A113445
• Derived Shabat linear tree transform of A053120: Triangle of coefficients of transformed Chebyshev's T(n, x) polynomials (powers of x in increasing order) T(x,n)->c*T(c*x+d)+d: c=-1;d=1; as substitution: 1-x->y( here alternative starting polynomial of Q(y,1]=1-y.at n=48A136203
• 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=58A136674
• Expansion of q^(-1/2) * (eta(q)^4 * eta(q^4)^2 / eta(q^2)^3)^2 in powers of q.at n=21A138502
• Expansion of ((phi(q) * phi(-q^2)^2)^2 - 1) / 4 in powers of q where phi() is a Ramanujan theta function.at n=42A138505
• a(n) = 1 - n^2.at n=43A258837
• G.f.: Re((2*i; x)_inf), where (a; q)_inf is the q-Pochhammer symbol, i = sqrt(-1).at n=27A292135
• Determinant of the matrix d*e/gcd(d, e)^2, where d, e run through the unitary divisors of n.at n=42A367064
• Dirichlet inverse of A341528, where A341528(n) = n * sigma(A003961(n)), and A003961 is fully multiplicative with a(prime(i)) = prime(i+1).at n=43A378228