id:A053866 - OEIS Search Results

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Parity of sum of divisors of n.

+0
5

0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0 (list; graph; listen)

	OFFSET	`0,1`
	LINKS	`Michael Gilleland, Some Self-Similar Integer Sequences`
	FORMULA	`a(n) = A000203(n) mod 2. a(n)=1 iff n>0 is a square or twice a square.` `Multiplicative with a(2^e)=1, a(p^e)=1 if e even, 0 otherwise.` `Dirichlet g.f.: zeta(2s)(1+2^-s). - Michael Somos Apr 12 2004`
	PROGRAM	`(PARI) a(n)=if(n<1, 0, issquare(n)\|issquare(2n)) / Michael Somos Apr 12 2004 */`
	CROSSREFS	`Cf. A000203, A028982.` `A093709(n)=a(n) if n>0.` `Sequence in context: A079336 A057215 A029691 this_sequence A156595 A143222 A010060` `Adjacent sequences: A053863 A053864 A053865 this_sequence A053867 A053868 A053869`
	KEYWORD	`nonn,mult`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Mar 29 2000`
	EXTENSIONS	`More terms from James A. Sellers (sellersj(AT)math.psu.edu), Apr 08 2000`

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Last modified December 18 21:37 EST 2009. Contains 171024 sequences.

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