id:A005091 - OEIS Search Results

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Number of primes = 3 mod 4 dividing n.

+0
4

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

	OFFSET	`1,21`
	FORMULA	`Additive with a(p^e) = 1 if p = 3 (mod 4), 0 otherwise.`
	PROGRAM	`(PARI) for(n=1, 100, print1(sumdiv(n, d, isprime(d)*if((d-3)%4, 0, 1)), ", "))`
	CROSSREFS	`Cf. A001221, A005089.` `Sequence in context: A077267 A134022 A085975 this_sequence A086831 A111405 A089053` `Adjacent sequences: A005088 A005089 A005090 this_sequence A005092 A005093 A005094`
	KEYWORD	`nonn`
	AUTHOR	`njas`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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