login
Odd powers of 2 written between a pair of 1's.
1

%I #7 Feb 10 2016 02:05:52

%S 121,181,1321,11281,15121,120481,181921,1327681,11310721,15242881,

%T 120971521,183886081,1335544321,11342177281,15368709121,121474836481,

%U 185899345921,1343597383681,11374389534721,15497558138881,121990232555521,187960930222081,1351843720888321,11407374883553281

%N Odd powers of 2 written between a pair of 1's.

%H Marius Coman, <a href="https://www.researchgate.net/profile/Marius_Coman/publication/277434066_Sequences_of_integers_conjectures_and_new_arithmetical_tools/links/556acca008aeccd7773a06c9.pdf"> Sequences of Integers, Conjectures and New Arithmetical Tools</a>, Education Publishing, Columbus, Ohio, 2015. See page 24.

%Y Cf. A000079, A004171.

%Y For primes see A268520.

%K nonn,base

%O 1,1

%A _N. J. A. Sloane_, Feb 10 2016