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A082065
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Greatest common prime-divisor of Phi[n]=A000010(n) and Sigma[2,n]=A001157(n); a(n)=1 if no common prime-divisor was found.
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4
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1, 1, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 5, 2, 2, 1, 2, 2, 3, 2, 2, 2, 1, 5, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 5, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 5, 2, 1, 2, 5, 2, 2, 2, 2, 2, 1, 2, 2, 5, 3, 5, 2, 2, 2, 1, 5, 2, 3, 2, 2, 2, 5, 2, 2, 2, 2, 5, 2, 2, 2, 2, 3, 2, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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MAPLE
| gcpd := proc(a, b) local g , d ; g := 1 ; for d in numtheory[divisors](a) intersect numtheory[divisors](b) do if isprime(d) then g := max(g, d) ; end if; end do: g ; end proc:
A082065 := proc(n) gcpd( numtheory[phi](n), numtheory[sigma][2](n) ) ; end proc:
seq(A082065(n), n=1..120) ; # R. J. Mathar, Jul 09 2011
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CROSSREFS
| Cf. A006530, A001157, A000010, A082061-A082066.
Sequence in context: A106028 A105307 A082071 * A082070 A082902 A123926
Adjacent sequences: A082062 A082063 A082064 * A082066 A082067 A082068
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Apr 07 2003
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EXTENSIONS
| Values corrected by R. J. Mathar, Jul 09 2011
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