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A179670 Numbers of the form p^3*q*r*s where p, q, r, and s are distinct primes. 9
840, 1320, 1560, 1848, 1890, 2040, 2184, 2280, 2760, 2856, 2970, 3080, 3192, 3432, 3480, 3510, 3640, 3720, 3864, 4158, 4440, 4488, 4590, 4760, 4872, 4914, 4920, 5016, 5130, 5160, 5208, 5250, 5304, 5320, 5640, 5720, 5928, 6072, 6210, 6216, 6360, 6426 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A050326(a(n)) = 7. - Reinhard Zumkeller, May 03 2013

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

Will Nicholes, Prime Signatures

Index to sequences related to prime signature

MATHEMATICA

f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 1, 1, 3}; Select[Range[10000], f]

PROG

(PARI) list(lim)=my(v=List(), t1, t2, t3); forprime(p=2, sqrtnint(lim\30, 3), t1=p^3; forprime(q=2, lim\(6*t1), if(q==p, next); t2=q*t1; forprime(r=2, lim\(2*t2), if(r==p || r==q, next); t3=r*t2; forprime(s=2, lim\t3, if(s==p || s==q || s==r, next); listput(v, t3*s))))); Set(v) \\ Charles R Greathouse IV, Aug 25 2016

CROSSREFS

Sequence in context: A068546 A033269 A272595 * A092002 A169827 A158402

Adjacent sequences:  A179667 A179668 A179669 * A179671 A179672 A179673

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jul 23 2010

STATUS

approved

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Last modified January 22 12:13 EST 2019. Contains 319363 sequences. (Running on oeis4.)