A122255 - OEIS

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A122255

Characteristic function of numbers with 3-smooth Euler's totient (A000010).

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`a(A122254(n)) = a(A048135(n)) = 1; a(A048136(n)) = 0;` `a(n) = if n=1 then 0 else A122256(n) - A122256(n-1);` `a(n) = A122261(n) for n < 25.`
	LINKS	`Index entries for characteristic functions`
	FORMULA	`a(n) = if A006530(A000010(n)) <= 3 then 1 else 0.`
	CROSSREFS	`Sequence in context: A136522 A086299 A152066 * A122261 A014922 A014988` `Adjacent sequences: A122252 A122253 A122254 * A122256 A122257 A122258`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 29 2006`

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Last modified February 15 12:25 EST 2012. Contains 205786 sequences.