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A179644 Product of the 4th power of a prime and 2 different distinct primes (p^4*q*r). 14
240, 336, 528, 560, 624, 810, 816, 880, 912, 1040, 1104, 1134, 1232, 1360, 1392, 1456, 1488, 1520, 1776, 1782, 1840, 1904, 1968, 2064, 2106, 2128, 2256, 2288, 2320, 2480, 2544, 2576, 2754, 2832, 2835, 2928, 2960, 2992, 3078, 3216, 3248, 3280, 3344, 3408 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

Prime Signatures

Index to sequences related to prime signature

EXAMPLE

240=2^4*3*5,336=2^4*3*7,..810=2^3^4*5,..

MAPLE

op(select(n->nops(factorset(n))=3 and sort([seq(op(2, a), a=ifactors(n)[2])])=[1, 1, 4], [$1..3408])); # Paolo P. Lava, Jul 18 2019

MATHEMATICA

f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 1, 4}; Select[Range[4000], f]

Take[Union[#[[1]]^4 #[[2]]#[[3]]&/@(Flatten[Permutations/@ Subsets[ Prime[ Range[ 20]], {3}], 1])], 50] (* Harvey P. Dale, Feb 07 2013 *)

PROG

(PARI) list(lim)=my(v=List(), t); forprime(p=2, (lim\6)^(1/4), forprime(q=2, sqrt(lim\p^4), if(p==q, next); t=p^4*q; forprime(r=q+1, lim\t, if(p==r, next); listput(v, t*r)))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jul 19 2011

CROSSREFS

Cf. A006881, A007304, A065036, A085986, A085987, A178739, A179642, A179643.

Sequence in context: A291921 A257413 A030638 * A099833 A272950 A255266

Adjacent sequences:  A179641 A179642 A179643 * A179645 A179646 A179647

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jul 21 2010

STATUS

approved

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Last modified December 11 07:31 EST 2019. Contains 329914 sequences. (Running on oeis4.)