OFFSET
1,2
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..2500
Clark Kimberling, Doubly interspersed sequences, double interspersions and fractal sequences, The Fibonacci Quarterly 48 (2010) 13-20.
EXAMPLE
Append the following segments:
1 2 3
1 2 4 3 5
1 2 4 6 3 5 7
1 2 4 6 8 3 5 7 9
For n>1, the n-th segment arises from the (n-1)st by inserting 2*n at position n+1 and appending 2*n+1 at position 2*n+1.
MATHEMATICA
Flatten[FoldList[Append[Insert[#1, 2 #2, #2 + 1], 2 #2 + 1] &, {1}, Range[10]]] (* Birkas Gyorgy, Jul 09 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jul 24 2009
STATUS
approved