(($_ > 0) ? ($last->[$_-1]) : ()),

# project-euler/75/75-analysis.txt

A | B | A^2 | B^2 | === | C^2 | C | A+B+C

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# project-euler/94/euler-94-almost-equilateral-triangles.pl

# For No. 1 we need a triangle for whose ($n-1) * sqrt($n^2 - (($n-1)/2)^2) is

# For No. 2 we need a triangle for whose ($n+1) * sqrt($n^2 - (($n+1)/2)^2) is

-# For No. 1, for "n" we need s = (3n-1)/2~~ ~~

+# For No. 1, for "n" we need s = (3n-1)/2

# area = sqrt{ (3n-1) / 2 * (n-1) / 2 * (n-1) / 2 * (n+1) / 2 }

# = 1/4 * (n-1) * sqrt { (3n-1)(n+1) }

-# Let's do m = n+1, then we get 1/4 * (m-2) * sqrt { (3m-4)m }~~ ~~

+# Let's do m = n+1, then we get 1/4 * (m-2) * sqrt { (3m-4)m }

# For No. 2, for "n" we need s = (3n+1)/2

# area = sqrt{ (3n+1) /2 * (n+1) / 2 * (n+1) / 2 * (n-1) / 2 }