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A091282
Exponent of 2 in prime(n)^2 - 1.
4
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, 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, 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
OFFSET
1,2
COMMENTS
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
Primes that give records for this sequence can be found in A233930. - Michel Marcus, Dec 20 2013
LINKS
FORMULA
a(n) = A023506(n) + A023512(n). - Amiram Eldar, Jun 06 2024
EXAMPLE
a(1)=0 since -1+2^s is always odd...
MATHEMATICA
IntegerExponent[Prime[Range[100]]^2 - 1, 2] (* Amiram Eldar, Jun 06 2024 *)
PROG
(PARI) a(n) = valuation(prime(n)^2-1, 2); \\ Michel Marcus, Dec 20 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jan 20 2004
EXTENSIONS
Definition modified by Michel Marcus, Dec 20 2013
STATUS
approved