The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A237992 Numbers which can be decomposed as pq + qr + rp (where p < q < r are distinct primes) in more ways than any smaller number. 1

%I #26 Mar 01 2014 05:27:44

%S 31,71,151,191,311,1031,1991,3191,5351,5591,10391,15791,17111,27191,

%T 31391,35591,42311,50951,70391,93551,107159,117911,119831,126551,

%U 166871,180311,191831,216191,255191,259871,327071,366791,435431,465911,514751,576551,599231,631991

%N Numbers which can be decomposed as pq + qr + rp (where p < q < r are distinct primes) in more ways than any smaller number.

%C Records in A238403.

%e 71 = 3*5 + 3*7 + 5*7 = 2*3 + 2*13 + 3*13 can be written in two ways, while smaller numbers can be written in at most one way.

%o (PARI) do(n)=my(v=vectorsmall(n),r); forprime(r=5,(n-6)\5, forprime(q=3, min((n-2*r)\(r+2),r-2), my(S=q+r,P=q*r); forprime(p=2,min((n-P)\S,q-1), v[p*S+P]++))); for(i=1,#v,if(v[i]>r,r=v[i];print1(i", "))

%Y Cf. A238403, A087053, A238397.

%K nonn

%O 1,1

%A _Charles R Greathouse IV_, Feb 26 2014

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 May 14 14:06 EDT 2024. Contains 372533 sequences. (Running on oeis4.)