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A065152
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Cototient(totient(n)) - totient(cototient(n)).
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2
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0, -1, 0, 0, 1, -1, 3, 0, 2, 0, 5, -2, 7, 0, -2, 0, 7, 0, 11, 0, 2, 2, 11, -4, 8, 2, 6, 0, 15, -6, 21, 0, 0, 2, 6, 0, 23, 4, 8, 0, 23, 0, 29, 4, 4, 4, 23, -8, 24, 4, -2, 4, 27, 0, 16, 0, 12, 8, 29, -12, 43, 6, 6, 0, 16, -10, 45, 4, 4, -6, 45, 0, 47, 6, 0, 8, 28, -2, 53, 0, 18, 12, 41, 0, 20, 10, 2, 8, 47, -4, 30, 8, 24, 8, 26, -16, 63, 6, 20, 8, 59, -8
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OFFSET
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1,7
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LINKS
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FORMULA
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EXAMPLE
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a(100) = 8, since phi(100) = 40, 100 - phi(100) = 60 = cototient(100), cototient(40) = 40 - 16 = 24, totient(60) = 16 so a(100) = 24 - 16 = 8.
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MATHEMATICA
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PROG
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(PARI) { for (n = 1, 1000, t=eulerphi(n); c=n - t; if (n>1, a=t - eulerphi(t) - eulerphi(c), a=0); write("b065152.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 13 2009
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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