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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A094378 Number of numbers having exactly n representations as ab+ac+bc with 0 < a < b < c. 4
 65, 23, 91, 40, 197, 39, 195, 56, 298, 87, 217, 60, 512, 97, 327, 77, 562, 125, 433, 88, 712, 125, 484, 115, 924, 121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Numbers up to 250,000 were checked. Note that there seem to be many more numbers having an even number of representations. Note that the Mathematica program computes A094376, A094377 and A094378, but outputs only this sequence. REFERENCES See A025052 LINKS EXAMPLE a(1) = 23 because there are 23 numbers (A093669) with unique representations. MATHEMATICA cntMax=10; nSol=Table[{0, 0, 0}, {cntMax+1}]; Do[lim=Ceiling[(n-2)/3]; cnt=0; Do[If[n>a*b && Mod[n-a*b, a+b]==0 && Quotient[n-a*b, a+b]>b, cnt++; If[cnt>cntMax, Break[]]], {a, 1, lim-1}, {b, a+1, lim}]; If[cnt<=cntMax, If[nSol[[cnt+1, 1]]==0, nSol[[cnt+1, 1]]=n]; nSol[[cnt+1, 2]]=n; nSol[[cnt+1, 3]]++; ], {n, 10000}]; Table[nSol[[i, 3]], {i, cntMax+1}] CROSSREFS Cf. A000926 (n having no representations), A093669 (n having one representation), A094376, A094377. Sequence in context: A034061 A113696 A302210 * A033385 A275484 A297941 Adjacent sequences:  A094375 A094376 A094377 * A094379 A094380 A094381 KEYWORD nonn AUTHOR T. D. Noe, Apr 28 2004 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.

Last modified August 19 20:38 EDT 2022. Contains 356231 sequences. (Running on oeis4.)