A189985 Numbers with prime factorization pqrstu^2.

60060, 78540, 87780, 90090, 92820, 103740, 106260, 117810, 125580, 131670, 133980, 135660, 139230, 143220, 145860, 150150, 155610, 158340, 159390, 163020, 164220, 169260, 170940, 183540, 188370, 189420, 196350, 197340, 198660, 200970

Offset

1,1

Links

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

Will Nicholes, Prime Signatures

Index to sequences related to prime signature

Mathematica

f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 1, 1, 1, 1, 2}; Select[Range[300000], f]

Prog

(PARI) list(lim)=my(v=List(), t1, t2, t3, t4, t5); forprime(p=2, sqrtint(lim\2310), t1=p^2; forprime(q=2, lim\(210*t1), if(q==p, next); t2=q*t1; forprime(r=2, lim\(30*t2), if(r==p || r==q, next); t3=r*t2; forprime(s=2, lim\(6*t3), if(s==p || s==q || s==r, next); t4=s*t3; forprime(t=2, lim\(2*t4), if(t==p || t==q || t==r || t==s, next); t5=t*t4; forprime(u=2, lim\t5, if(u==p || u==q || u==r || u==s || u==t, next); listput(v, t5*u))))))); Set(v) \\ Charles R Greathouse IV, Aug 25 2016

Crossrefs

Cf. A179693, A189984.

Sequence in context: A344359 A043635 A106774 * A338606 A287047 A075671

Adjacent sequences: A189982 A189983 A189984 * A189986 A189987 A189988

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 03 2011

Status

approved