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A190474 Numbers with prime factorization pqr^2s^6. 2
20160, 31680, 33600, 37440, 44352, 47040, 48960, 52416, 52800, 54720, 62400, 66240, 68544, 76608, 81600, 82368, 83520, 89280, 91200, 92736, 102060, 103488, 106560, 107712, 110400, 116160, 116928, 118080, 120384, 122304, 123200, 123840 (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, 2, 6}; Select[Range[300000], f]

PROG

(PARI) list(lim)=my(v=List(), t1, t2, t3); forprime(p=2, sqrtnint(lim\60, 6), t1=p^6; forprime(q=2, sqrtint(lim\(6*t1)), if(q==p, next); t2=q^2*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

Cf. A190472, A190473.

Sequence in context: A186480 A204864 A145535 * A109479 A003808 A011786

Adjacent sequences:  A190471 A190472 A190473 * A190475 A190476 A190477

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, May 10 2011

STATUS

approved

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Last modified May 5 18:59 EDT 2021. Contains 343573 sequences. (Running on oeis4.)