A172199 Number of numbers with 2n+1 digits that are lunar squares.

10, 90, 900, 9000, 74667, 608673

Offset: 1

Author

David Applegate, Marc LeBrun and N. J. A. Sloane, Jan 20 2011

Keywords

• nonn
• base
• more

Comments

Every lunar square (see A087019) has an odd number of digits. Lunar squares with <= 7 digits are all distinct, but for longer numbers there are many examples of pairs of numbers whose lunar squares coincide.

Links

• D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]
• Index entries for sequences related to dismal (or lunar) arithmetic

Crossrefs

Cf. A087019, A180513, A181319.