A190380 Numbers with prime factorization pqrst^2u^2.

180180, 235620, 263340, 278460, 300300, 311220, 318780, 376740, 392700, 401940, 406980, 420420, 429660, 437580, 438900, 450450, 464100, 475020, 489060, 492660, 507780, 512820, 518700, 531300, 549780, 550620, 568260, 589050, 592020, 595980

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, 2, 2}; Select[Range[1000000], f]

Prog

(PARI) list(lim)=my(v=List(), t1, t2, t3, t4, t5); forprime(p=2, sqrtint(lim\4620), t1=p^2; forprime(q=2, sqrtint(lim\(210*t1)), if(q==p, next); t2=q^2*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. A190378, A190379.

Sequence in context: A362807 A204787 A060232 * A235716 A274365 A209828

Adjacent sequences: A190377 A190378 A190379 * A190381 A190382 A190383

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 09 2011

Status

approved