Thanks to everyone who made a donation during our annual appeal! To see the list of donors, or make a donation, see the OEIS Foundation home page.
1,2
Comparing with A165722 there is one additional term a(8)=9.
No other terms below 10^5.
Table of n, a(n) for n=1..22.
(PARI) isok(n) = (sumdigits(16^n-1) % n) == 0; \\ Michel Marcus, Oct 16 2013
Cf. A165722.
Sequence in context: A063949 A073518 A144769 * A033104 A191325 A190209
Adjacent sequences: A165734 A165735 A165736 * A165738 A165739 A165740
base,more,nonn
Zak Seidov, Sep 25 2009
approved