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A054571
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a(n) = phi(n - phi(n)), a(1) = 0.
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9
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0, 1, 1, 1, 1, 2, 1, 2, 2, 2, 1, 4, 1, 4, 6, 4, 1, 4, 1, 4, 6, 4, 1, 8, 4, 6, 6, 8, 1, 10, 1, 8, 12, 6, 10, 8, 1, 8, 8, 8, 1, 8, 1, 8, 12, 8, 1, 16, 6, 8, 18, 12, 1, 12, 8, 16, 12, 8, 1, 20, 1, 16, 18, 16, 16, 22, 1, 12, 20, 22, 1, 16, 1, 18, 24, 16, 16, 18, 1, 16, 18
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,6
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LINKS
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FORMULA
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MAPLE
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n-numtheory[phi](n) ;
end proc:
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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J. Sandor (mstaicu(AT)dualnet.ro), Mar 09 2002
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EXTENSIONS
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Description clarified with a(1) = 0 explicitly set by convention. - Antti Karttunen, Aug 07 2017
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STATUS
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approved
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