A100748 Years of recorded appearances of Halley's Comet (negative years are B.C.).

-240, -164, -86, -11, 66, 141, 218, 295, 374, 451, 530, 607, 684, 760, 837, 912, 989, 1066, 1145, 1222, 1301, 1378, 1456, 1531, 1607, 1682, 1759, 1835, 1910, 1985

Offset: 1

Author

David Terr, Jan 03 2005

Keywords

• sign

Comments

This sequence is not well-defined for many reasons (negative years are ill-defined; calendars change often, so when does a year begin?; what does "observed" mean?; what if the comet was observed both at the end of one year and at the beginning of another, as in 1985/1986?; etc.). - N. J. A. Sloane, Jun 24 2007

Examples

			a(30) = 1985 because the 30th recorded appearance of Halley's comet was in 1985.
		

Links

• Joseph M. Laufer, Halley's Comet, Its 30th Recorded Return, 1985-1986.

Crossrefs

See A072235 for another version.