A169821 a(n) = n*n in carryless arithmetic mod 9 in base 10.

0, 1, 4, 0, 7, 7, 0, 4, 1, 0, 100, 121, 144, 160, 187, 117, 130, 154, 171, 100, 400, 441, 484, 430, 477, 427, 460, 414, 451, 400, 0, 61, 34, 0, 67, 37, 0, 64, 31, 0, 700, 781, 774, 760, 757, 747, 730, 724, 711, 700, 700, 711, 724, 730, 747, 757, 760, 774, 781, 700, 0, 31, 64

Offset: 0

Author

David Applegate, Marc LeBrun and N. J. A. Sloane, Jul 11 2010

Keywords

• nonn
• base

Comments

Addition and multiplication are the same as in school, that is, done in base 10, except that there are no carries and individual digits are added or multiplied mod 9.

Examples

			13*13 = 160:
..13
..13
----
..30
.13.
----
.160
----
		

Links

• Index entries for sequences related to carryless arithmetic

Crossrefs

Cf. A010878, A169908. See A170990 for a better version.