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A056626
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Number of non-unitary square divisors of n.
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0
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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; refs; listen; history; internal format)
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OFFSET
| 1,64
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FORMULA
| a(n)=A046951(n)-2^r, where r is the number of prime factors in the largest unitary prime divisor of n.
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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.
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CROSSREFS
| Cf. A046951, A034444, A000188, A055229, A008833.
Sequence in context: A162641 A087781 A181009 * A091398 A062103 A112314
Adjacent sequences: A056623 A056624 A056625 * A056627 A056628 A056629
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Aug 08 2000
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