OFFSET
1,3
LINKS
Eric M. Schmidt, Table of n, a(n) for n = 1..10000
Sourav Sen Gupta, Nirupam Kar, Subhamoy Maitra, Santanu Sarkar, and Pantelimon Stanica, Counting Heron triangles with Constraints, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 13, Paper A3, 2013.
Eric Weisstein's World of Mathematics, Heronian Triangle.
EXAMPLE
For n = 3, the two triangles have side lengths (3, 4, 5) and (5, 5, 8), with areas 6 and 12 respectively.
PROG
(Sage) def A221838(n) : pyth = (number_of_divisors(n^2 if n%2==1 else (n/2)^2) - 1) // 2; return pyth^2 + pyth
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric M. Schmidt, Jan 27 2013
STATUS
approved