-821
domain: Z
Appears in sequences
- Expansion of (9*phi(q)*phi(q^3)^5 - phi(q)^5*phi(q^3))/8 in powers of q where phi(q) is a Ramanujan theta function.at n=32A113261
- G.f.: Product_{k>0} (1-x^(4k-1)) / (1-x^(4k-2)).at n=55A131795
- Expansion of (1/3) * b(q) * b(q^2) * c(q)^2 / c(q^2) in powers of q where b(), c() are cubic AGM functions.at n=32A132000
- Expansion of eta(q)^5 * eta(q^3) * eta(q^6)^4 / eta(q^2)^4 in powers of q.at n=31A214262
- Inverse Euler transform of the number of prime factors (with multiplicity) function A001222.at n=49A320776
- a(n) = -n^2 + 21*n - 1.at n=40A332884
- Partial alternating sums of the sigma_2 function: a(n) = Sum_{k=1..n} (-1)^(k+1) * sigma_2(k).at n=21A379921