A087601 Primes occurring as lesser side of Heronian triangle (sides are consecutive integers, area and inradius are integers).
3, 13, 193, 37633, 7300801, 1416317953
Offset: 1
Examples
a(1)=3 because 3, 4 and 5 are sides of Heronian triangle (area is 6, inradius is 1).
References
- Mohammad K. Azarian, Circumradius and Inradius, Problem S125, Math Horizons, Vol. 15, Issue 4, April 2008, p. 32. Solution published in Vol. 16, Issue 2, November 2008, p. 32.
Formula
Prime elements of A016064. Alternatively, primes p such that 3*(p+1)^2-12 is a square, i.e., p+1 belongs to A003500. - Max Alekseyev, May 14 2010
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