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A366534
The number of unitary divisors of the exponentially odd numbers (A268335).
6
1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 2, 2, 4, 4, 2, 4, 4, 2, 2, 8, 2, 2, 4, 4, 4, 2, 4, 4, 4, 2, 8, 2, 4, 2, 4, 2, 4, 4, 4, 4, 4, 2, 2, 4, 4, 8, 2, 4, 8, 2, 2, 4, 4, 8, 2, 4, 2, 4, 4, 4, 4, 2, 4, 4, 4, 4, 4, 2, 2, 8, 2, 4, 8, 4, 2, 2, 8, 4, 2, 8, 4, 4, 4, 8, 4
OFFSET
1,2
LINKS
FORMULA
a(n) = A034444(A268335(n)).
MATHEMATICA
f[n_] := Module[{e = FactorInteger[n][[;; , 2]]}, If[AllTrue[e, OddQ], 2^Length[e], Nothing]]; f[1] = 1; Array[f, 150]
PROG
(PARI) lista(max) = for(k = 1, max, my(e = factor(k)[, 2], isexpodd = 1); for(i = 1, #e, if(!(e[i] % 2), isexpodd = 0; break)); if(isexpodd, print1(2^(#e), ", ")));
CROSSREFS
Similar sequences: A366536, A366538.
Sequence in context: A049716 A361289 A188903 * A066671 A159802 A329586
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, Oct 12 2023
STATUS
approved