OFFSET
0,1
COMMENTS
The symbols // denote concatenation of digits in the definition, and d(n) denotes n repetitions of d, n >= 0.
Conjecture: satisfies a linear recurrence having signature (1111, -112110, 1111000, -1000000). - Harvey P. Dale, Nov 23 2022
LINKS
Syed Iddi Hasan, Table of n, a(n) for n = 0..165
FORMULA
If d(n) denotes n repetitions of the digit d, then a(n) = 5(n)49(n+1)4(n)5, where n >= 0.
EXAMPLE
549945 is a fixed point of the mapping for n=1.
MATHEMATICA
Table[FromDigits[Join[PadRight[{}, n, 5], {4}, PadRight[{}, n+1, 9], PadRight[{}, n, 4], {5}]], {n, 0, 15}] (* Harvey P. Dale, Nov 23 2022 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Syed Iddi Hasan, Jul 20 2012
STATUS
approved