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 even integers are indicated here by parentheses; the successive block-sizes are 1, 2, 3, 4, 6,... which reproduces the sequence itself: 1, (2), 3, (4, 6), 5, 7, (8, 10, 12), 9, 11, 13, (14, 16, 18, 20), 15, 17, 19, 21, (22, 24, 26, 28, 30, 32), 23, 25, 27, 29, 31, 33, (34, 36, 38, 40, 42), 35, 37, 39, 41, 43...
MATHEMATICA
s={1, 2, 3, 4, 6}; k=2; ev={4, 6}; Do[od=Range[ev[[1]]+1, ev[[-1]]+1, 2]; s=Flatten@{s, od}; a=od[[-1]]+1; k++; ev=Range[a, a+2*s[[k]]-2, 2]; s=Flatten@{s, ev}, {50}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Eric Angelini, Jul 28 2016
STATUS
approved