http://oeis.org/A014221 LINKS: Robert G. Wilson v, Table of n, a(n) for n = 0..5 [I deleted a(6) from the b-file because it is too large for the system to handle. - N. J. A. Sloane, Apr 17 2014] Whatever was done, the link doesn't (currently) work (for me). Not that we need it since all six terms are listed.