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

1,1

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, 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

Cf. A190292, A190293.

Sequence in context: A237335 A206410 A283527 * A124047 A113008 A004935

Adjacent sequences: A190291 A190292 A190293 * A190295 A190296 A190297

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 07 2011

Status

approved