The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A051585 Number of integer-sided triangles of area 6n. 6
 1, 2, 0, 2, 1, 2, 1, 2, 1, 4, 1, 1, 0, 4, 2, 2, 0, 2, 1, 4, 3, 1, 0, 2, 1, 2, 0, 4, 0, 2, 0, 2, 1, 1, 6, 3, 0, 0, 1, 5, 0, 3, 0, 3, 2, 0, 0, 2, 1, 4, 1, 0, 0, 2, 4, 8, 0, 0, 0, 5, 0, 0, 1, 2, 1, 3, 0, 1, 0, 15, 0, 2, 0, 0, 0, 4, 2, 1, 0, 5, 1, 0, 0, 6, 2, 0, 1, 3, 0, 4, 3, 0, 0, 0, 1, 2, 0, 2, 1, 2, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS If integer-sided triangle has integer area, area is divisible by 6. LINKS Giovanni Resta, Table of n, a(n) for n = 1..10000 PROG (PARI) a(n)=sum(z=sqrtint(sqrtint(192*n^2)-1)+1, sqrtint(9*(64*n^2+5)\20), sum(y=z\2+1, z, my(t=(y*z)^2-(12*n)^2, x); if(issquare(t, &t), (issquare(y^2+z^2-2*t, &x) && x<=y) + (t && issquare(y^2+z^2+2*t, &x) && x<=y), 0))) \\ Charles R Greathouse IV, Jun 27 2013 CROSSREFS Cf. A051584, A051586. Sequence in context: A107455 A039701 A025822 * A049115 A294204 A329697 Adjacent sequences:  A051582 A051583 A051584 * A051586 A051587 A051588 KEYWORD nonn AUTHOR 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 2 09:22 EDT 2021. Contains 346422 sequences. (Running on oeis4.)