# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a249484 Showing 1-1 of 1 %I A249484 #12 Jan 02 2023 12:30:51 %S A249484 1,2,4,3,5,2,7,9,4,3,6,8,5,2,7,10,12,9,4,3,6,11,13,8,5,2,7,10,15,17, %T A249484 12,9,4,3,6,11,14,16,13,8,5,2,7,10,15,18,20,17,12,9,4,3,6,11,14,19,21, %U A249484 16,13,8,5,2,7,10,15,18,23,25,20,17,12,9,4,3,6 %N A249484 Sequence which reappears when consecutive terms are erased iff they have the same parity. %H A249484 Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 %H A249484 Éric Angelini, More fractal triangles, SeqFan list, Jan 12 2015. %e A249484 . 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| %e A249484 . 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 %e A249484 . 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 %e A249484 . : 1 _ _ _ _ 2 _ _ 4 3 _ _ 5 2 7 _ _ 9 4 3 6 _ _ 8 5 . %o A249484 (Haskell) %o A249484 a249484 n = a249484_list !! n %o A249484 a249484_list = 1 : concat (zipWith (++) ([2] : f [5,2,7]) (f [4,3])) where %o A249484 f = iterate (\row -> [g $ head row] ++ row ++ [g $ last row]) %o A249484 g x = x + ((5 -) . (* 2) . flip mod 2) x %Y A249484 Cf. A249900. %K A249484 nonn %O A249484 0,2 %A A249484 _Eric Angelini_ and _Reinhard Zumkeller_, Jan 13 2015 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE