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A065986
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Numbers n such that Sigma(n) = EulerPhi(n+1) + EulerPhi(n) + EulerPhi(n-1).
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1
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6, 147, 286, 376, 534, 738, 805, 2392, 2406, 4324, 8214, 9606, 10362, 12126, 16263, 17511, 27639, 29151, 39215, 48616, 60687, 61132, 61915
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,60
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EXAMPLE
| Sigma(6) = 12 = 6 + 2 + 4 = EulerPhi(7) + EulerPhi(6) + EulerPhi(5).
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PROG
| (PARI) { n=e1=e2=0; for (m=2, 10^9, e2=e1; e1=e; e=eulerphi(m+1); if (sigma(m) == e + e1 + e2, write("b065986.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 05 2009]
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CROSSREFS
| Cf. A000010.
Sequence in context: A166809 A063419 A099185 * A199226 A012791 A089480
Adjacent sequences: A065983 A065984 A065985 * A065987 A065988 A065989
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KEYWORD
| nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Dec 10 2001
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