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A179209
Numbers k such that 2^(2*k-1) mod (2*k+1) = 2.
1
1, 4, 7, 10, 16, 19, 25, 28, 31, 34, 43, 46, 55, 61, 64, 70, 79, 88, 91, 97, 100, 106, 109, 118, 124, 133, 145, 151, 154, 157, 160, 163, 169, 190, 196, 199, 205, 208, 223, 226, 235, 244, 250, 259, 268, 271, 286, 289, 295, 298, 316, 334, 340, 343, 346, 349, 358, 361, 365, 376, 385, 394
OFFSET
1,2
LINKS
FORMULA
{ k : A178970(n) = 2 }.
MATHEMATICA
Select[Range[400], PowerMod[2, 2#-1, 2#+1]==2&] (* Harvey P. Dale, Aug 16 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved