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Search: id:A072416
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| A072416 |
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a(1) = 2; a(n) = half of the a(n-1)-th even nontotient number. |
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+0
3
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| 2, 13, 49, 149, 373, 835, 1727, 3383, 6341, 11419, 19966, 34067, 56967, 93578, 151313, 241281, 379934
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(5)=373=746/2, where 746 is the a(4)=149-th term in A005277.
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MATHEMATICA
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a = Table[0, {10^6}]; Do[b = EulerPhi[n]/2; If[b < 10^6 + 1, a[[b]] = 1], {n, 1, 2 10^7}]; b = Select[ Range[10^6], a[[ # ]] == 0 &]; c = 2; Do[ Print[c]; c = b[[c]], {n, 0, 17}]
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CROSSREFS
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Cf. A006508, A071255, A005277, A072415.
Sequence in context: A002534 A117717 A005584 this_sequence A056305 A056297 A037383
Adjacent sequences: A072413 A072414 A072415 this_sequence A072417 A072418 A072419
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KEYWORD
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more,nonn
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AUTHOR
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Labos E. (labos(AT)ana.soete.hu), Jun 17 2002
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EXTENSIONS
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Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 20 2002
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