id:A032438 - OEIS Search Results

Search: id:A032438

Displaying 1-1 of 1 results found.

page 1

n^2-floor( (n+1)/2 )^2.

+0
3

0, 0, 3, 5, 12, 16, 27, 33, 48, 56, 75, 85, 108, 120, 147, 161, 192, 208, 243, 261, 300, 320, 363, 385, 432, 456, 507, 533, 588, 616, 675, 705, 768, 800, 867, 901, 972, 1008, 1083, 1121, 1200, 1240, 1323, 1365 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`The answer to a question from Mike and Laurie Crain (2crains(AT)concentric.net): how many even numbers are there in an n X n multiplication table starting at 1X1?`
	FORMULA	`G.f. x^2(x^2+2x+3)/(1-x^2)^2/(1-x). - Ralf Stephan, Jun 10 2003`
	CROSSREFS	`First differences are in A059029.` `Sequence in context: A080560 A151866 A057587 this_sequence A025083 A126471 A024696` `Adjacent sequences: A032435 A032436 A032437 this_sequence A032439 A032440 A032441`
	KEYWORD	`nonn,easy,nice`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`

page 1

Search completed in 0.002 seconds

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

AT&T Labs Research