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A023593 Exponent of least prime factor of 2*prime(n)+1. 2
1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,6
LINKS
EXAMPLE
a(6) = 3 because 2*prime(6)+1 = 27 = 3^3.
MAPLE
A023593 := proc(n)
A067029(2*ithprime(n)+1) ;
end proc: # R. J. Mathar, Jul 08 2015
MATHEMATICA
Table[FactorInteger[2*Prime[n] + 1][[1]][[2]], {n, 100}] (* Clark Kimberling, Oct 01 2013 *)
CROSSREFS
Sequence in context: A366168 A016565 A051714 * A353755 A353784 A117544
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected by Clark Kimberling, Oct 01 2013
STATUS
approved

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Last modified March 19 01:22 EDT 2024. Contains 370952 sequences. (Running on oeis4.)