A190294 Numbers with prime factorization pqr^3s^4.
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
Keywords
Links
- T. D. Noe, Table of n, a(n) for n = 1..1000
- Will Nicholes,Prime Signatures
Programs
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Mathematica
f[n_]:=Sort[Last/@FactorInteger[n]]=={1,1,3,4};Select[Range[150000],f] -
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