OFFSET
1,3
COMMENTS
Each integer appears twice. If one deletes the first occurrence of each positive integer one obtains the sequence of positive integers: 1,2,3,4,5,...; i.e., if we enclose in parentheses the first occurrence of 1,2,3,... giving (1),1,(2),2,(3),(4),3,(5),4,(6),(7),5,(8),6,(9),7,(10),... and remove them, we obtain: 1,2,3,4,5,6,7,... The same property holds if one deletes the second occurrence of each positive integer. - Benoit Cloitre, Oct 13 2007
LINKS
Eric Weisstein's World of Mathematics, Graham-Pollak Sequence
FORMULA
Sequence is completely defined by: a(floor(n*(1+sqrt(2))))=n; a(floor(n*(1+1/sqrt(2))))=n, n>=1 since A003151 and A003152 are Beatty sequences partitioning the integers. - Benoit Cloitre, Oct 13 2007
EXAMPLE
-1+sqrt(2), -1+sqrt(2), -2+2*sqrt(2), -2+2*sqrt(2), -4+3*sqrt(2), ..., so the sequence of multipliers is 1, 1, 2, 2, 3, ...
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Jan 18 2004
STATUS
approved