1,2

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

nonn

Jon Perry, Feb 19 2002

Edited by Dean Hickerson, Feb 22 2002

approved