OFFSET
1,2
COMMENTS
The sequence starts with a(1)=1 and is always extended with the smallest integer not yet in the sequence which does not lead to a contradiction. The sequence is a permutation of the natural numbers.
LINKS
EXAMPLE
The blocks of odd integers are indicated here by parentheses; the successive block-sizes are1,2,3,5,4,6,7,9,11,8,10,... which reproduces the sequence itself:
(1),2,(3,5),4,6,(7,9,11),8,10,12,(13,15,17,19,21),14,16,18,20,22,(23,25,27,29),24,26,28,30,(31,33,35,37,39,41),
32,34,36,38,40,42,(43,45,47,49,51,53,55),44,46,48,50,52,54,56,(57,59,61,63,65,67,69,71,73),58,60,62,64,66,68,70,72,74,
(75,77,79,81,83,85,87,89,91,93,95),76,78,80,82,84,86,88,90,92,94,96,(97,99,101,103,105,107,109,111),
98,100,102,104,106,108,110,112,(113,115,117,119,121,123,125,127,129,131),...
MATHEMATICA
s={1, 2, 3, 5}; k=2; od={3, 5}; Do[ev=Range[od[[1]]+1, od[[-1]]+1, 2]; s=Flatten@{s, ev}; a=ev[[-1]]+1; k++; od=Range[a, a+2*s[[k]]-2, 2]; s=Flatten@{s, od}, {100}]; s
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov and Eric Angelini, Jul 28 2016
STATUS
approved