A020479 - OEIS

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A020479

Number of noninvertible 2 X 2 matrices over Z/nZ (determinant is a divisor of 0).

10, 33, 160, 145, 1008, 385, 2560, 2673, 7120, 1441, 16128, 2353, 26320, 27585, 40960, 5185, 81648, 7201, 113920, 97713, 155056, 12673, 258048, 90625, 299728, 216513, 421120, 25201, 671760, 30721, 655360, 552321, 866320, 532945, 1306368, 51985 (list; graph; refs; listen; history; internal format)

	OFFSET	`2,1`
	FORMULA	`a(n) seems to be divisible by n. - Ralf Stephan (ralf(AT)ark.in-berlin.de), Sep 01 2003` `a(n)=n^4-A000252(n). - T. D. Noe (noe(AT)sspectra.com), Jan 16 2006`
	CROSSREFS	`Sequence in context: A020478 A094170 A004638 * A140866 A177221 A045087` `Adjacent sequences: A020476 A020477 A020478 * A020480 A020481 A020482`
	KEYWORD	`nonn`
	AUTHOR	`David W. Wilson (davidwwilson(AT)comcast.net)`

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Last modified February 15 12:05 EST 2012. Contains 205782 sequences.