id:A056626 - OEIS Search Results

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Number of non-unitary square divisors of n.

+0
1

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

	OFFSET	`1,64`
	FORMULA	`a(n)=A046951(n)-2^r, where r is the number of prime factors in the largest unitary prime divisor of n.`
	EXAMPLE	`n=p^u prime-power has u+1 square-divisors of which 2 (i.e. 1 and n) are unitary but u-1 are not unitary, so a[p^u]=u-1. E.g. n=4^4=256, has 5 square divisors {1,4,16,64,256} of which {4,16,64} are not unitary, so a(256)=3.`
	CROSSREFS	`Cf. A046951, A034444, A000188, A055229, A008833.` `Sequence in context: A102354 A162641 A087781 this_sequence A091398 A062103 A112314` `Adjacent sequences: A056623 A056624 A056625 this_sequence A056627 A056628 A056629`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Aug 08 2000`

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Last modified November 30 13:13 EST 2009. Contains 167758 sequences.

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