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A130670 Smallest k such that phi(x) = k has exactly n even solutions. 4
1, 2, 4, 8, 16, 32, 24, 80, 48, 160, 72, 216, 96, 792, 360, 144, 192, 1056, 1512, 1080, 240, 288, 432, 1248, 3200, 1200, 768, 3120, 480, 576, 2496, 720, 1536, 864, 6000, 3600, 2016, 3072, 960, 3168, 3744, 1152, 11664, 2688, 2400, 2160, 9792, 1728, 6240, 9072 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vladeta Jovovic and Donovan Johnson, Table of n, a(n) for n = 1..1000 (first 100 terms from Vladeta Jovovic)

EXAMPLE

a(3) = 4 because there are 3 even solutions (8, 10, 12) of phi(x) = 4 and for all k < 4 the number of even solutions of phi(x) = k is unequal to 3.

CROSSREFS

Cf. A007374, A130669.

Sequence in context: A070350 A070349 A070348 * A070340 A036124 A070339

Adjacent sequences:  A130667 A130668 A130669 * A130671 A130672 A130673

KEYWORD

nonn

AUTHOR

Franz Vrabec, Jun 27 2007

STATUS

approved

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Last modified April 21 19:16 EDT 2021. Contains 343156 sequences. (Running on oeis4.)