A067544 - OEIS

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A067544

Numbers n such that phi(n*(n+1)*(n+2)/6)/phi(n*(n+1)/2) is not an integer where phi(n)=A000010(n) is the Euler totient function.

8, 9, 18, 27, 44, 45, 53, 62, 80, 81, 90, 98, 99, 108, 116, 126, 134, 135, 143, 162, 171, 189, 198, 224, 225, 233, 234, 251, 260, 261, 270, 279, 287, 288, 296, 315, 332, 350, 351, 387, 413, 422, 423, 441, 449, 450, 458, 459, 468, 476, 477, 503, 504, 512, 522 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Often a(k)==0 (mod 3) and if a(k+1)-a(k)=1 then a(k+1)==0 (mod 3)`
	CROSSREFS	`Sequence in context: A050706 A159836 A069809 * A022313 A120311 A061414` `Adjacent sequences: A067541 A067542 A067543 * A067545 A067546 A067547`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 28 2002`

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Last modified February 15 23:53 EST 2012. Contains 205860 sequences.