-1377

Appears in sequences

• Expansion of Product_{k>=1} (1 - x^k)^9.at n=28A010817
• arctan(sec(x)*arctan(x))=x-1/3!*x^3+33/5!*x^5-1377/7!*x^7+99649/9!*x^9...at n=3A012805
• Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^18 in powers of x.at n=8A047643
• Dirichlet inverse of sigma_4 function (A001159).at n=17A053826
• Determinant of the n X n Hankel matrix whose entries are s_2 (i+j), 0 <= i, j < n, where s_2 is the sum of the base-2 bits.at n=38A056886
• a(n) = (n+1)*(2-n)/2.at n=53A080956
• Expansion of g.f.: -x*(1 - 2*x + 6*x^2 - 2*x^3 + x^4)/((1-x)^3*(1+x)^4).at n=16A122576
• Expansion of g.f. 1+x+(1+3*x+x^2)/(1+x)^3.at n=52A201163
• Values of n such that L(15) and N(15) are both prime, where L(k) = (n^2+n+1)*2^(2*k) + (2*n+1)*2^k + 1, N(k) = (n^2+n+1)*2^k + n.at n=22A227518
• Alternating sum of heptagonal numbers.at n=33A266085
• G.f.: Sum_{n=-oo..+oo} x^n * (1 - x^n)^(3*n).at n=53A268298
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 181", based on the 5-celled von Neumann neighborhood.at n=19A270629
• Expansion of exp( Sum_{n>=1} -sigma(9*n)*x^n/n ) in powers of x.at n=6A283169
• a(n) = Sum_{k=0..n} (-1)^k * 2^k * p(k), where p(k) is the partition function A000041.at n=7A293464
• Inverse Euler transform of the unsigned Moebius function A008966.at n=52A320782