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A190294
Numbers with prime factorization pqr^3s^4.
3
15120, 22680, 23760, 28080, 33264, 35640, 36720, 39312, 41040, 42000, 42120, 49680, 49896, 51408, 55080, 57456, 58968, 61560, 61776, 62640, 66000, 66960, 69552, 74520, 77112, 78000, 79920, 80784, 82320, 86184, 87696, 88560, 90288, 92664
OFFSET
1,1
LINKS
MATHEMATICA
f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 1, 3, 4}; Select[Range[150000], f]
PROG
(PARI) list(lim)=my(v=List(), t1, t2, t3); forprime(p=2, sqrtnint(lim\120, 4), t1=p^4; forprime(q=2, sqrtnint(lim\(6*t1), 3), if(q==p, next); t2=q^3*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: A237335 A206410 A283527 * A124047 A113008 A004935
KEYWORD
nonn
AUTHOR
STATUS
approved