

A050259


Numbers n such that 2^n == 3 (mod n).


21




OFFSET

1,2


COMMENTS

No other terms below 10^17.  Max Alekseyev, Oct 24 2016
Terms were computed: a(2) by the Lehmers, a(3) by Max Alekseyev, a(4) and a(5) by Joe K. Crump, a(?) = 63130707451134435989380140059866138830623361447484274774099906755 by P.L. Montgomery.


REFERENCES

R. Daniel Mauldin and S. M. Ulam, Mathematical problems and games. Adv. in Appl. Math. 8 (1987), pp. 281344.


LINKS

Table of n, a(n) for n=1..5.
Joe K. Crump, 2^n mod n
R. K. Guy, The Strong Law of Small Numbers, Amer. Math. Monthly 95 (1988), pp. 697712. See example 13.
R. K. Guy, The strong law of small numbers. Amer. Math. Monthly 95 (1988), no. 8, 697712. [Annotated scanned copy]
Eric Weisstein's World of Mathematics, 2
OEIS Wiki, 2^n mod n


PROG

(PARI) is(n)=Mod(2, n)^n==3 \\ Charles R Greathouse IV, Jun 11 2015


CROSSREFS

Cf. A001567, A036236, A015940, A015910.
Sequence in context: A199631 A124977 A128172 * A249972 A233494 A175568
Adjacent sequences: A050256 A050257 A050258 * A050260 A050261 A050262


KEYWORD

nonn,more,hard


AUTHOR

Eric W. Weisstein


EXTENSIONS

a(1)a(5) certified by Max Alekseyev, Jan 27 2007, Apr 27 2009.


STATUS

approved



