OFFSET
0,2
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
Éric Angelini, More fractal triangles, SeqFan list, Jan 12 2015.
EXAMPLE
. n : 0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|
. a(n): 1 2 4 3 5 2 7 9 4 3 6 8 5 2 7 10 12 9 4 3 6 11 13 8 5
. 0/1 : 1 0 0 1 1 0 1 1 0 1 0 0 1 0 1 0 0 1 0 1 0 1 1 0 1
. : 1 _ _ _ _ 2 _ _ 4 3 _ _ 5 2 7 _ _ 9 4 3 6 _ _ 8 5 .
PROG
(Haskell)
a249484 n = a249484_list !! n
a249484_list = 1 : concat (zipWith (++) ([2] : f [5, 2, 7]) (f [4, 3])) where
f = iterate (\row -> [g $ head row] ++ row ++ [g $ last row])
g x = x + ((5 -) . (* 2) . flip mod 2) x
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric Angelini and Reinhard Zumkeller, Jan 13 2015
STATUS
approved