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A372469
a(n) = log_2(A372468(n)).
3
0, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 3, 2, 2, 1, 3, 1, 2, 2, 2, 1, 2, 2, 3, 1, 3, 1, 2, 1, 2, 1, 3, 2, 3, 2, 2, 1, 1, 2, 2, 3, 1, 2, 3, 1, 1, 2, 2, 3, 1, 2, 1, 2, 2, 2, 3, 1, 2, 2, 2, 2, 1, 1, 3, 1, 3, 3, 2, 1, 1, 3, 2, 1, 3, 2, 2, 2, 4, 2, 2, 2
OFFSET
1,5
LINKS
MATHEMATICA
f[n_] := Module[{p = Times @@ (1 + FactorInteger[n][[;; , 2]]), e}, e = IntegerExponent[p, 2]; If[p == 2^e, e, Nothing]]; f[1] = 0; Array[f, 150]
PROG
(PARI) lista(kmax) = {my(p, e); for(k = 1, kmax, p = vecprod(apply(x -> x + 1, factor(k)[, 2])); e = valuation(p, 2); if(p >> e == 1, print1(e, ", "))); }
CROSSREFS
Cf. A372468.
Sequence in context: A332292 A054350 A026606 * A265918 A207676 A161175
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, May 02 2024
STATUS
approved