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A189983 Numbers with prime factorization pqrst^2. 1
4620, 5460, 6930, 7140, 7980, 8190, 8580, 9660, 10710, 11220, 11550, 11970, 12012, 12180, 12540, 12870, 13020, 13260, 13650, 14490, 14820, 15180, 15540, 15708, 16170, 16830, 17220, 17556, 17850, 17940, 18018, 18060, 18270, 18564, 18810, 19110, 19140, 19380 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

Will Nicholes, Prime Signatures

MATHEMATICA

f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 1, 1, 1, 2}; Select[Range[30000], f]

PROG

(PARI) list(lim)=my(v=List(), t1, t2, t3, t4); forprime(p=2, sqrtint(lim\210), t1=p^2; forprime(q=2, lim\(30*t1), if(q==p, next); t2=q*t1; forprime(r=2, lim\(6*t2), if(r==p || r==q, next); t3=r*t2; forprime(s=2, lim\(2*t3), if(s==p || s==q || s==r, next); t4=s*t3; forprime(t=2, lim\t4, if(t==p || t==q || t==r || t==s, next); listput(v, t4*t)))))); Set(v) \\ Charles R Greathouse IV, Aug 25 2016

CROSSREFS

Cf. A178740, A179644, A179670.

Sequence in context: A265926 A260054 A253115 * A295431 A237634 A051649

Adjacent sequences:  A189980 A189981 A189982 * A189984 A189985 A189986

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, May 03 2011

STATUS

approved

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Last modified May 25 11:27 EDT 2020. Contains 334592 sequences. (Running on oeis4.)