A056139 - OEIS

This site is supported by donations to The OEIS Foundation.

A056139

n^2-primefloor[n]*primeceiling[n].

0, 0, 1, 0, 1, 0, -13, 4, 23, 0, 1, 0, -25, 4, 35, 0, 1, 0, -37, 4, 47, 0, -91, -42, 9, 62, 117, 0, 1, 0, -123, -58, 9, 78, 149, 0, -73, 4, 83, 0, 1, 0, -85, 4, 95, 0, -187, -90, 9 (list; graph; refs; listen; history; internal format)

	OFFSET	`2,7`
	COMMENTS	`a(n)=0 iff n is prime`
	FORMULA	`a(n)=n^2-A007917(n)*A007918(n) =A000290(n)-A030664(n)`
	EXAMPLE	`a(3)=3^2-33=0, a(4)=4^2-35=1`
	CROSSREFS	`Cf. A056140, A056141.` `Sequence in context: A204594 A204157 A010219 * A106293 A046734 A123172` `Adjacent sequences: A056136 A056137 A056138 * A056140 A056141 A056142`
	KEYWORD	`easy,sign`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Jun 15 2000`

Content is available under The OEIS End-User License Agreement .

Last modified February 16 21:30 EST 2012. Contains 205971 sequences.