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A180644 Numbers n such that 3+phi(n)^2 is a prime 0
3, 4, 5, 6, 8, 10, 11, 12, 15, 16, 20, 22, 23, 24, 29, 30, 46, 53, 58, 71, 85, 106, 107, 113, 128, 131, 136, 141, 142, 145, 160, 170, 173, 179, 187, 188, 192, 204, 205, 213, 214, 226, 232, 240, 257, 262, 282, 284, 290, 317, 328, 346, 348, 352, 358, 374, 400, 410 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

a(15)=29 since 3+phi(29)^2=3+28^2=787 is prime

CROSSREFS

Cf. A000010

Sequence in context: A039031 A047309 A121502 * A202110 A267858 A108943

Adjacent sequences: A180641 A180642 A180643 * A180645 A180646 A180647

KEYWORD

nonn

AUTHOR

Carmine Suriano, Sep 14 2010

STATUS

approved

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Last modified January 27 09:55 EST 2023. Contains 359838 sequences. (Running on oeis4.)