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A057327 First member of a prime quadruple in a 2p-1 progression. 13
1531, 2131, 2311, 3061, 6211, 6841, 7411, 10321, 13681, 15391, 16651, 18121, 22531, 23011, 24391, 29671, 30781, 31771, 33301, 35311, 41491, 44371, 46411, 54601, 56311, 57991, 60331, 61381, 66601, 67651, 78031, 83431, 85381, 88741 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Numbers n such that n remains prime through 3 iterations of function f(x) = 2x - 1.
LINKS
EXAMPLE
Quadruplets are (1531,3061,6121,12241), (2131,4261,8521,17041), ...
MATHEMATICA
Select[Prime[Range[9000]], And@@PrimeQ[NestList[2#-1&, #, 3]]&] (* Harvey P. Dale, May 27 2012 *)
CROSSREFS
Sequence in context: A030061 A122707 A347200 * A057328 A110022 A339075
KEYWORD
nonn
AUTHOR
Patrick De Geest, Aug 15 2000
STATUS
approved

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Last modified April 19 08:45 EDT 2024. Contains 371782 sequences. (Running on oeis4.)