The associative array of a sequence 
is the array 
, where 
is the 
th index 
for which 
. Here, 
is required to be an infinitive
sequence: for every 
, 
for infinitely many 
. As 
and 
range through 
, 
ranges through all of 
.
Associative Array
See also
Fractal Sequence, Infinitive SequenceExplore with Wolfram|Alpha
References
Kimberling, C. "Fractal Sequences and Interspersions." Ars Combin. 45, 157-168, 1997.Referenced on Wolfram|Alpha
Associative ArrayCite this as:
Weisstein, Eric W. "Associative Array." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/AssociativeArray.html