Pb on A117871
reismann at free.fr
reismann at free.fr
Mon May 7 19:49:24 CEST 2007
Dear Neil, seqfans,
There is a little pb on A117871 :
%S A117871 0,0,4,3,4,5,3,7,4,3,4,11,3,13,4,3,4,17,3,19,4,3,4,23,3,5,4,3...
Def :
%N A117871 Smallest divisor of 2n that is > 2, or 0 if no such divisor exists.
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The sequence of these definition is :
0,4,3,4,5,3,7,4,3,4,11,3,13,4,3,4,17,3,19,4,3,4,23,3,5,4,3...
It's the decomposition of even numbers in weight*level (gap=cste=0).
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The definition for the sequence :
%S A117871 0,0,4,3,4,5,3,7,4,3,4,11,3,13,4,3,4,17,3,19,4,3,4,23,3,5,4,3...
is :
Smallest divisor of 2n-2 that is > 2, or 0 if no such divisor exists.
or :
a(n) = smallest k such that 2 = 2n mod k, or 0 if no such k exists.
It's the decomposition of even numbers in weight*level+gap (gap=cste=2).
Best,
Rémi
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