OFFSET
1,1
COMMENTS
The numbers that are the product of two such distinct odd numbers x*y are in A337715. - Bernard Schott, Oct 14 2020
EXAMPLE
341 * 341 is a term because 2^341 mod 341 = 2.
MATHEMATICA
okQ[x_, y_] := PowerMod[2, x, y] == PowerMod[2, y, x] == 2; n =10000; Union[Reap[Do[If[i*j < nn && okQ[i, j], Sow[i*j]], {i, 1, nn/3, 2}, {j, i, nn/3, 2}]][[2, 1]]] (* Harvey P. Dale, Jan 21 2011 *)
PROG
(PARI) isok(n) = {if ((n % 2), fordiv(n, d, if ((d >= n/d) && (lift(Mod(2, d)^(n/d)) == 2) && (lift(Mod(2, n/d)^d) == 2), return(1)); ); ); } \\ Michel Marcus, Sep 17 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jan 15 2011
EXTENSIONS
Definition clarified by T. D. Noe, Jan 17 2011
Corrected and extended by Harvey P. Dale, Jan 21 2011
STATUS
approved