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A166985 Primes of the form phi(n)/2. 0
2, 3, 2, 3, 2, 5, 2, 3, 3, 5, 11, 11, 23, 29, 41, 23, 53, 29, 41, 83, 89, 53, 113, 131, 83, 173, 89, 179, 191, 113, 233, 239, 251, 131, 281, 293, 173, 179, 359, 191, 419, 431, 443, 233, 239, 491, 251, 509, 281, 293, 593, 641, 653, 659, 683, 359, 719, 743, 761, 809, 419 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..61.

EXAMPLE

a(1)=2 (=phi(5)/2); a(2)=3 (=phi(7)/2); a(3)=2 (=phi(8)/2); a(4)=3 (=phi(9)/2); a(5)=2 (=phi(10)/2); a(6)=5 (=phi(11)/2).

CROSSREFS

Cf. A000010, A000040.

Cf. A005384. [From R. J. Mathar, Oct 28 2009]

Sequence in context: A060395 A016026 A086757 * A046215 A256113 A256368

Adjacent sequences:  A166982 A166983 A166984 * A166986 A166987 A166988

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Oct 26 2009

EXTENSIONS

Extended by R. J. Mathar, Oct 28 2009

STATUS

approved

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Last modified September 24 09:10 EDT 2021. Contains 347630 sequences. (Running on oeis4.)