A190387 Numbers with prime factorization pq^2r^2s^2t^2.

485100, 573300, 749700, 762300, 837900, 1014300, 1064700, 1067220, 1278900, 1367100, 1415700, 1490580, 1631700, 1673100, 1778700, 1808100, 1820700, 1851300, 1896300, 2069100, 2072700, 2274300, 2337300, 2484300, 2504700, 2548980, 2585700

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, 2, 2, 2, 2}; Select[Range[4000000], f]
Take[(Times@@(#^{1, 2, 2, 2, 2}))&/@Flatten[Permutations[#]&/@Subsets[ Prime[ Range[ 20]], {5}], 1]//Union, 50] (* Harvey P. Dale, Jan 18 2020 *)

Prog

(PARI) list(lim)=my(v=List(), t1, t2, t3, t4); forprime(p=2, sqrtint(lim\6300), t1=p^2; forprime(q=2, sqrtint(lim\(180*t1)), if(q==p, next); t2=q^2*t1; forprime(r=2, sqrtint(lim\(12*t2)), if(r==p || r==q, next); t3=r^2*t2; forprime(s=2, sqrtint(lim\(2*t3)), if(s==p || s==q || s==r, next); t4=s^2*t3; forprime(t=2, lim\t4, if(t==p || t==q || t==r || t==s, next); listput(v, t4*t)))))); Set(v) \\ Charles R Greathouse IV, Aug 25 2016

Crossrefs

Cf. A190384, A190385, A190386.

Sequence in context: A048425 A205036 A205284 * A183695 A216070 A163401

Adjacent sequences: A190384 A190385 A190386 * A190388 A190389 A190390

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 09 2011

Status

approved