

A271410


LCM of exponents in binary expansion of 2n.


8



1, 1, 2, 2, 3, 3, 6, 6, 4, 4, 4, 4, 12, 12, 12, 12, 5, 5, 10, 10, 15, 15, 30, 30, 20, 20, 20, 20, 60, 60, 60, 60, 6, 6, 6, 6, 6, 6, 6, 6, 12, 12, 12, 12, 12, 12, 12, 12, 30, 30, 30, 30, 30, 30, 30, 30, 60, 60, 60, 60, 60, 60, 60, 60, 7, 7, 14, 14, 21, 21, 42
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OFFSET

0,3


LINKS

Peter Kagey, Table of n, a(n) for n = 0..10000


EXAMPLE

a(2) = lcm(2) = 2 because 2*2 = 2^2;
a(3) = lcm(1, 2) = 2 because 2*3 = 2^1 + 2^2;
a(7) = lcm(1, 2, 3) = 6 because 2*7 = 2^3 + 2^2 + 2^1.


MATHEMATICA

lcm[n_]:=Module[{idn2=IntegerDigits[n, 2]}, LCM@@Pick[Reverse[Range[ Length[ idn2]]], idn2, 1]]; Join[{1}, Array[lcm, 100]] (* Harvey P. Dale, Jan 24 2019 *)


PROG

(PARI) a(n) = my(ve = select(x>x==1, Vecrev(binary(2*n)), 1)); lcm(vector(#ve, k, ve[k]1)); \\ Michel Marcus, Apr 12 2016
(PARI) a(n)=lcm(Vec(select(x>x, Vecrev(binary(n)), 1))) \\ Charles R Greathouse IV, Apr 12 2016


CROSSREFS

Cf. A029931, A064894, A073642, A096111, A116417.
Sequence in context: A239962 A175175 A116417 * A196055 A145787 A096111
Adjacent sequences: A271407 A271408 A271409 * A271411 A271412 A271413


KEYWORD

nonn


AUTHOR

Peter Kagey, Apr 11 2016


STATUS

approved



