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A147575 Numbers with exactly 8 distinct prime divisors {2,3,5,7,11,13,17,19}. 12
9699690, 19399380, 29099070, 38798760, 48498450, 58198140, 67897830, 77597520, 87297210, 96996900, 106696590, 116396280, 126095970, 135795660, 145495350, 155195040, 164894730, 174594420, 184294110, 193993800, 203693490, 213393180, 232792560, 242492250, 252191940 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Successive numbers k such that EulerPhi[x]/x = m

( Family of sequences for successive n primes )

m=1/2 numbers with exactly 1 distinct prime divisor {2} see A000079

m=1/3 numbers with exactly 2 distinct prime divisors {2,3} see A033845

m=4/15 numbers with exactly 3 distinct prime divisors {2,3,5} see A143207

m=8/35 numbers with exactly 4 distinct prime divisors {2,3,5,7} see A147571

m=16/77 numbers with exactly 5 distinct prime divisors {2,3,5,7,11} see A147572

m=192/1001 numbers with exactly 6 distinct prime divisors {2,3,5,7,11,13} see A147573

m=3072/17017 numbers with exactly 7 distinct prime divisors {2,3,5,7,11,13,17} see A147574

m=55296/323323 numbers with exactly 8 distinct prime divisors {2,3,5,7,11,13,17,19} see A147575

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = 9699690 * A080682(n). - Amiram Eldar, Mar 10 2020

MATHEMATICA

a = {}; Do[If[EulerPhi[9699690 x] == 1658880 x, AppendTo[a, 9699690 x]], {x, 1, 100}]; a

CROSSREFS

Cf. A060735, A080682, A143207, A147571-A147575, A147576-A147580.

Sequence in context: A147713 A123322 A258363 * A046326 A154573 A058332

Adjacent sequences:  A147572 A147573 A147574 * A147576 A147577 A147578

KEYWORD

nonn

AUTHOR

Artur Jasinski, Nov 07 2008

EXTENSIONS

More terms from Amiram Eldar, Mar 10 2020

STATUS

approved

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Last modified August 13 08:27 EDT 2020. Contains 336442 sequences. (Running on oeis4.)