4913508489domain: NAppears in sequencesA Chebyshev transform of the Catalan numbers.at n=21A101499Imaginary part of a Gaussian integer sequence with a Gaussian integer Somos-4 Hankel transform.at n=21A183894Imaginary part of a Gaussian integer sequence with a Gaussian integer Somos-4 Hankel transform.at n=22A183894