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%I #9 Dec 20 2013 09:06:45
%S 0,3,3,4,3,3,5,3,4,3,6,3,4,3,5,3,3,3,3,4,4,5,3,4,6,3,4,3,3,5,8,3,4,3,
%T 3,4,3,3,4,3,3,3,7,7,3,4,3,6,3,3,4,5,5,3,9,4,3,5,3,4,3,3,3,4,4,3,3,5,
%U 3,3,6,4,5,3,3,8,3,3,5,4,3,3,5,5,4,3,7,4,3,5,3,6,4,3,3,4,3,4,3,3,3,3,3,4,3
%N Exponent of 2 in prime(n)^2 - 1.
%C Also, exponent of 2 in -1+prime(n)^s if s is an exponent of the form 4k+2 (previous definition). - _Michel Marcus_, Dec 20 2013
%C Primes that give records for this sequence can be found in A233930. - _Michel Marcus_, Dec 20 2013
%e a(1)=0 since -1+2^s is always odd...
%o (PARI) a(n) = valuation(prime(n)^2-1, 2); \\ _Michel Marcus_, Dec 20 2013
%Y Cf. A007814, A023506, A091283, A091284.
%K nonn
%O 1,2
%A _Labos Elemer_, Jan 20 2004
%E Definition modified by _Michel Marcus_, Dec 20 2013
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