1,2

The standard definition of a ring requires that multiplication be associative, so these are very nonstandard rings.

The rings need not contain a multiplicative unit.

This sequence may be multiplicative. - Mitch Harris, Apr 19 2005

Cf. A027623.

Sequence in context: A156467 A015167 A086204 this_sequence A028372 A130678 A156523

Adjacent sequences: A037289 A037290 A037291 this_sequence A037293 A037294 A037295

nonn

Christian G. Bower (bowerc(AT)usa.net), Jun 15 1998. In fact more is known:

1,2,2,55,2,4,2,801288,165,4,2,110,2,4,4,?,2,330,2,110,4,4,2,1602576