8168202domain: NAppears in sequencesDenominator of Euler(n, 1/21).at n=5A156762Dirichlet g.f.: Product_{k>=2} 1 / (1 - k^(-s))^(k^5).at n=20A343285Dirichlet g.f.: Product_{k>=2} (1 + k^(-s))^(k^5).at n=20A343325