id:A005089 - OEIS Search Results

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Number of primes = 1 mod 4 dividing n.

+0
4

0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 2, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0 (list; graph; listen)

	OFFSET	`1,65`
	FORMULA	`Additive with a(p^e) = 1 if p = 1 (mod 4), 0 otherwise.`
	PROGRAM	`(PARI) for(n=1, 100, print1(sumdiv(n, d, isprime(d)*if((d-1)%4, 0, 1)), ", "))`
	CROSSREFS	`Cf. A001221.` `Sequence in context: A165766 A102082 A030199 this_sequence A119395 A087476 A035162` `Adjacent sequences: A005086 A005087 A005088 this_sequence A005090 A005091 A005092`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.

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