A372469 - OEIS

A372469

a(n) = log_2(A372468(n)).

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

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OFFSET

1,5

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

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

Adjacent sequences: A372466 A372467 A372468 * A372470 A372471 A372472

KEYWORD

nonn,easy

AUTHOR

Amiram Eldar, May 02 2024

STATUS

approved