login
This site is supported by donations to The OEIS Foundation.

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A176879 Numbers that are the product of 3 distinct primes a,b and c, such that a^2+b^2+c^2 are averages of twin prime pairs. 1
110, 130, 430, 442, 470, 670, 782, 790, 890, 970, 1222, 1310, 1358, 1462, 1582, 1670, 1898, 1978, 2338, 2410, 2510, 3082, 3170, 3478, 3970, 4090, 4430, 4718, 4982, 5402, 5410, 5542, 5678, 6298, 7390, 7582, 7918, 7922, 8570, 8878, 9062, 9178, 9682, 9698 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

110=2*5*11; 2^2+5^2+11^2=150+-1 -> primes

LINKS

Table of n, a(n) for n=1..44.

MATHEMATICA

l[n_]:=Last/@FactorInteger[n]; f[n_]:=First/@FactorInteger[n]; lst={}; Do[If[l[n]=={1, 1, 1}, a=f[n][[1]]; b=f[n][[2]]; c=f[n][[3]]; If[PrimeQ[a^2+b^2+c^2-1]&&PrimeQ[a^2+b^2+c^2+1], AppendTo[lst, n]]], {n, 8!}]; lst

CROSSREFS

Cf. A006881, A014574, A176875, A176876, A176877, A176878

Sequence in context: A073494 A073488 A244389 * A039447 A095611 A200070

Adjacent sequences:  A176876 A176877 A176878 * A176880 A176881 A176882

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 27 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 | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified May 30 06:51 EDT 2017. Contains 287302 sequences.