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A057826 Greatest number with totient 2n (or zero when no such number exists). 9
6, 12, 18, 30, 22, 42, 0, 60, 54, 66, 46, 90, 0, 58, 62, 120, 0, 126, 0, 150, 98, 138, 94, 210, 0, 106, 162, 174, 118, 198, 0, 240, 134, 0, 142, 270, 0, 0, 158, 330, 166, 294, 0, 276, 0, 282, 0, 420, 0, 250, 206, 318, 214, 378, 242, 348, 0, 354, 0, 462, 0, 0, 254, 510 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
If a(n) = 0, n is a nontotient number - see (A005277)/2.
LINKS
MATHEMATICA
a = Table[0, {100}]; Do[ t = EulerPhi[n]/2; If[t < 101, a[[t]] = n], {n, 1, 10^3}]; a
CROSSREFS
Bisection of A057635. Cf. A000010, A005277, A002181.
Sequence in context: A350685 A270383 A088345 * A334543 A330853 A268657
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Nov 08 2000
STATUS
approved

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Last modified March 19 06:53 EDT 2024. Contains 370953 sequences. (Running on oeis4.)