OFFSET
1,19
PROG
(Haskell)
a249856 = sum . map (flip mod 2) . (uss !!)
uss = [] : [] : [] : f 2 1 [3..] where
f x y zs = g zs [] where
g (v:vs) ws | gcd v y > 1 || gcd v x > 1 = g vs (v : ws)
| otherwise = ws : f v x (delete v zs)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Nov 09 2014
STATUS
approved