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Consists of 1, even perfect numbers and numbers of the form n(n+1)/2 where n+1 is a Fermat prime. (See A068194 for proof.)
Table of n, a(n) for n=1..15.
Jon Perry, Erdos-Moser
Cf. A000396, A000668, A019434, A068194.
Record values in A082184.
Sequence in context: A197435 A240514 A115887 * A080506 A109163 A109490
Adjacent sequences: A068192 A068193 A068194 * A068196 A068197 A068198
Jon Perry, Feb 19 2002
Edited by Dean Hickerson, Feb 22 2002