-259

Appears in sequences

• a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.at n=36A002120
• Expansion of x*cos(sin(x)), odd terms only.at n=3A009042
• Expansion of sin(sinh(x)*cos(x)).at n=3A009495
• Determinant of the n X n matrix whose element (i,j) equals f(|i-j|) where f(n) is the sum of middle divisors (A071090).at n=7A071547
• Engel expansion for (negative) constant defined in A078756.at n=10A080231
• Consider the triangle in which the n-th row starts with n, contains n terms and the difference of successive terms is 1,2,3,... up to n-1. Sequence gives row sums.at n=13A081498
• Expansion of 1/(1 - x + x^4).at n=45A099530
• Coefficients of the A-Rogers-Selberg identity.at n=41A104408
• Numerators of the triangle of coefficients T(n,k), read by rows, that satisfy: y^x = Sum_{n=0..x} R_n(y)*x^n for all nonnegative integers x, y, where R_n(y) = Sum_{k=0..n} T(n,k)*y^k and T(n,k) = a(n,k)/A107046(n,k).at n=22A107045
• Sum(mu(i)*phi(j): i+j=n), with mu=A008683 and phi=A000010.at n=65A112962
• Triangle, real terms extracted from squares of paired terms in arithmetic sequences.at n=38A121164
• Center antidiagonal four in a tri-antidiagonal n-th Matrix generated triangular sequence: first element as 4==m[1,1,1].at n=16A124028
• Expansion of 1/(1+7*x*c(x)), c(x) the g.f. of Catalan numbers A000108.at n=3A127016
• 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=31A140882
• a(n) = -5*a(n-1) + 7*a(n-2) for n > 1 with a(0) = 1 and a(1) = -7.at n=3A152239
• a(n) = -3a(n-1) - 3a(n-2) - 2a(n-3), n > 3.at n=9A158927
• Fluctuations of the number of cubefree integers not exceeding 2^n.at n=61A160115
• A symmetrical triangle sequence:q=3:t(n,m,q)=(1 - q^n)*Eulerian[n + 1, m] - (1 - q^n) + 1.at n=7A174729
• A symmetrical triangle sequence:q=3:t(n,m,q)=(1 - q^n)*Eulerian[n + 1, m] - (1 - q^n) + 1.at n=8A174729
• E.g.f.: A(x) = Sum_{n>=0} log(1+x)^[n*phi] / [n*phi]!, where [n*phi] = A000201(n), the lower Wythoff sequence, and phi = (1+sqrt(5))/2.at n=6A180869