OFFSET
0,3
COMMENTS
A261923(m) != 5 for m <= 10^5.
The same for m <= 5*10^8. - Michel Marcus, Sep 20 2023
a(5) <= 10718873460460617403023221866359404479. - Michael S. Branicky, Sep 21 2023
From Michael S. Branicky, Sep 21 2023: (Start)
a(n) exists for all n. Proof. Let b(i) be the binary representation of i. Let L be its length, and let w = 0^L be a string of L 0's. Then a(n+1) <= u = b(1)wb(2)w...wb(a(n)-1) since u contains the binary representation of each number less than a(n) but not that of a(n). So, A261923(u) = 1 + A261923(a(n)). (End)
PROG
(Haskell)
import Data.List (elemIndex); import Data.Maybe (fromJust)
a262279 = fromJust . (`elemIndex` a261923_list)
(PARI) a(n) = my(k=0); while (A261923(k) != n, k++); k; \\ Michel Marcus, Sep 20 2023
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Reinhard Zumkeller, Sep 17 2015
STATUS
proposed