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A061468
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a(n) = d(n) + phi(n), where d(n) is the number of divisors (A000005) and phi(n) is Euler's totient function (A000010).
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10
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2, 3, 4, 5, 6, 6, 8, 8, 9, 8, 12, 10, 14, 10, 12, 13, 18, 12, 20, 14, 16, 14, 24, 16, 23, 16, 22, 18, 30, 16, 32, 22, 24, 20, 28, 21, 38, 22, 28, 24, 42, 20, 44, 26, 30, 26, 48, 26, 45, 26, 36, 30, 54, 26, 44, 32, 40, 32, 60, 28, 62, 34, 42, 39, 52, 28
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OFFSET
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1,1
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COMMENTS
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If d(n) increases phi(n) tends to go down so the sum has a significance.
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LINKS
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EXAMPLE
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a(20) = d(20) + phi(20) = 6 + 8 = 14.
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MAPLE
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with(numtheory); A061468 := n-> tau(n) + phi(n);
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MATHEMATICA
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Table[DivisorSigma[0, n]+EulerPhi[n], {n, 70}] (* Harvey P. Dale, Aug 22 2020 *)
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PROG
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(PARI) { for (n=1, 1000, write("b061468.txt", n, " ", numdiv(n) + eulerphi(n)) ) } \\ Harry J. Smith, Jul 23 2009
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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More terms from Winston C. Yang (winston(AT)cs.wisc.edu), May 19 2001
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STATUS
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approved
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