login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A130526
A permutation of the integers induced by the lower and upper Wythoff sequences.
2
0, 1, -1, 2, 3, -2, 4, -3, 5, 6, -4, 7, 8, -5, 9, -6, 10, 11, -7, 12, -8, 13, 14, -9, 15, 16, -10, 17, -11, 18, 19, -12, 20, 21, -13, 22, -14, 23, 24, -15, 25, -16, 26, 27, -17, 28, 29, -18, 30, -19, 31, 32, -20, 33, -21, 34, 35, -22, 36, 37, -23, 38, -24, 39, 40, -25, 41, 42, -26
OFFSET
0,4
COMMENTS
Another permutation of the integers is -A130526.
FORMULA
a(0) = 0; a(n)=k if n=L(k); a(n)=-k if n=U(k), where L(k) = A000201(k)=Floor(n*phi) = Lower Wythoff sequence, U(k) = A001950(k) = k+L(k) = Upper Wythoff sequence.
EXAMPLE
6=L(4), so a(6)=4.
7=U(3), so a(7)=-3.
CROSSREFS
KEYWORD
sign
AUTHOR
Clark Kimberling, Jun 02 2007
STATUS
approved