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A023592 Least odd prime divisor of 2*prime(n)+1. 4
5, 7, 11, 3, 23, 3, 5, 3, 47, 59, 3, 3, 83, 3, 5, 107, 7, 3, 3, 11, 3, 3, 167, 179, 3, 7, 3, 5, 3, 227, 3, 263, 5, 3, 13, 3, 3, 3, 5, 347, 359, 3, 383, 3, 5, 3, 3, 3, 5, 3, 467, 479, 3, 503, 5, 17, 7, 3, 3, 563, 3, 587, 3, 7, 3, 5, 3, 3, 5, 3, 7, 719, 3, 3, 3, 13, 19, 3, 11, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
Table[FactorInteger[2*Prime[n] + 1][[1, 1]], {n, 1, 80}] (* Amiram Eldar, Mar 05 2020 *)
PROG
(PARI) a(n) = factor(2*prime(n)+1)[1, 1]; \\ Michel Marcus, Oct 02 2013
CROSSREFS
Except for first term, same as A094460.
Sequence in context: A059303 A061523 A119653 * A076546 A167372 A023590
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 29 04:59 EDT 2024. Contains 371264 sequences. (Running on oeis4.)