login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A178739 Product of the 4th power of a prime (A030514) and a different prime (p^4*q). 32
48, 80, 112, 162, 176, 208, 272, 304, 368, 405, 464, 496, 567, 592, 656, 688, 752, 848, 891, 944, 976, 1053, 1072, 1136, 1168, 1250, 1264, 1328, 1377, 1424, 1539, 1552, 1616, 1648, 1712, 1744, 1808, 1863, 1875, 2032, 2096, 2192, 2224, 2349, 2384, 2416, 2511 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A030628.

LINKS

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

Index to sequences related to prime signature

FORMULA

Solutions of the equation tau(n^9)=37*tau(n). - Paolo P. Lava, Mar 15 2013

a(n) ~ kn log n with k = 1/P(4) = 1/A085964 = 12.98817.... - Charles R Greathouse IV, Feb 23 2017

MAPLE

with(numtheory);

A178739:=proc(q) local n;

for n from 1 to q do if tau(n^9)=37*tau(n) then print(n); fi; od; end:

A178739(10^10); # Paolo P. Lava, Mar 15 2013

MATHEMATICA

f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 4}; Select[Range[10000], f] (* Vladimir Joseph Stephan Orlovsky, May 03 2011 *)

max = 500000; A178739 = DeleteCases[Union[Table[Prime[p] Prime[q]^4 Boole[p != q], {p, PrimePi[max/16]}, {q, PrimePi[max/2]}]], 0]; Take[A178739, 50] (* Alonso del Arte, Aug 05 2012 *)

PROG

(PARI) list(lim)=my(v=List(), t); forprime(p=2, (lim\2)^(1/4), t=p^4; forprime(q=2, lim\t, if(p==q, next); listput(v, t*q))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jul 20 2011

CROSSREFS

Cf. A065036, A030514, A030628, A085986, A085987.

Sequence in context: A110229 A108608 A030628 * A261548 A065911 A260841

Adjacent sequences: A178736 A178737 A178738 * A178740 A178741 A178742

KEYWORD

easy,nonn

AUTHOR

Will Nicholes, Jun 08 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 1 00:42 EST 2022. Contains 358453 sequences. (Running on oeis4.)