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A364802 Smallest number that reaches 1 after n iterations of the map x -> A356874(x). 1
1, 2, 3, 5, 11, 29, 117, 879, 15279, 963957, 392158939, 2059426052079 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
a(n) is the smallest number k such that A364800(k) = n.
LINKS
MATHEMATICA
f[n_] := f[n] = Module[{d = IntegerDigits[n, 2], nd}, nd = Length[d]; Total[d * Fibonacci[Range[nd, 1, -1]]]]; (* A356874 *)
iternum[n_] := Length@ NestWhileList[f, n, # > 1 &] - 1; (* A364800 *)
seq[kmax_] := Module[{s = {}, imax = -1, i}, Do[i = iternum[k]; If[i > imax, imax = i; AppendTo[s, k]], {k, 1, kmax}]; s]
seq[10^6]
PROG
(PARI) f(n) = {my(b = binary(n), nb = #b); sum(i = 1, nb, b[i] * fibonacci(nb - i + 1)); } \\ A356874
iternum(n) = if(n == 1, 0, iternum(f(n)) + 1); \\ A364800
lista(kmax) = {my(imax = -1, i1); for(k = 1, kmax, i = iternum(k); if(i > imax, imax = i; print1(k, ", "))); }
CROSSREFS
Similar sequences: A007755, A364803.
Sequence in context: A173631 A182987 A334814 * A360815 A087580 A072535
KEYWORD
nonn,base,more
AUTHOR
Amiram Eldar, Aug 08 2023
EXTENSIONS
a(11) from Martin Ehrenstein, Aug 26 2023
STATUS
approved

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Last modified July 20 18:09 EDT 2024. Contains 374459 sequences. (Running on oeis4.)