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A329204
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Number of integers less than n having at least as many totatives as n.
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1
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0, 1, 0, 1, 0, 3, 0, 2, 1, 4, 0, 6, 0, 4, 2, 3, 0, 8, 0, 6, 3, 5, 0, 10, 1, 6, 3, 8, 0, 16, 0, 7, 4, 9, 2, 15, 0, 9, 4, 14, 0, 21, 0, 10, 7, 9, 0, 21, 2, 15, 5, 11, 0, 22, 5, 14, 7, 11, 0, 33, 0, 12, 10, 12, 3, 29, 0, 15, 6, 26, 0, 28, 0, 16, 13, 18, 4, 34, 0, 24, 7, 17
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OFFSET
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1,6
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LINKS
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EXAMPLE
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a(6) = 3, because 6 has 2 totatives and there are 3 integers less than 6 with 2 or more totatives: 3 with 2 totatives, 4 with 2 totatives, and 5 with 4 totatives.
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MATHEMATICA
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Table[Length[Select[Range[n-1], EulerPhi[#]>=EulerPhi[n]&]], {n, 1, 100}]
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PROG
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(PARI) a(n) = sum(k=1, n-1, eulerphi(k) >= eulerphi(n)); \\ Michel Marcus, Nov 22 2019
(PARI) first(n)=my(u=vectorsmall(n), v=vector(n)); forfactored(f=1, n, u[f[1]]=eulerphi(f)); for(i=1, n, v[i]=sum(j=1, i-1, u[j]>=u[i])); v \\ Charles R Greathouse IV, Dec 11 2019
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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