OFFSET
1,4
COMMENTS
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
Rémy Sigrist, PARI program for A290885
EXAMPLE
Let f be the function z -> z * (1+i), and g the function z -> (z-1) * (1+i) + 1.
S(1) = 0 by definition; so a(1) = 0.
f(S(1)) = 0 has already occurred.
g(S(1)) = -i has not yet occurred; so S(2) = -i and a(2) = -1.
f(S(2)) = 1 - i has not yet occurred; so S(3) = 1 - i and a(3) = -1.
g(S(2)) = 1 - 2*i has not yet occurred; so S(4) = 1 - 2*i and a(4) = -2.
f(S(3)) = 2 has not yet occurred; so S(5) = 2 and a(5) = 0.
g(S(3)) = 2 - i has not yet occurred; so S(6) = 2 - i and a(6) = -1.
f(S(4)) = 3 - i has not yet occurred; so S(7) = 3 - i and a(7) = -1.
g(S(4)) = 3 - 2*i has not yet occurred; so S(8) = 3 - 2*i and a(8) = -2.
PROG
(PARI) See Links section.
(PARI) a(n) = -real(subst(Pol(binary(n-1)), 'x, I+1)); \\ Kevin Ryde, Apr 08 2020
CROSSREFS
KEYWORD
sign,look
AUTHOR
Rémy Sigrist, Aug 13 2017
STATUS
approved