OFFSET
1,2
COMMENTS
This sequence is a binary variant of A053582.
Dirichlet's theorem on arithmetic progressions guaranties that this sequence is infinite.
We can build a similar sequence for any base b > 1 and any starting value coprime to b.
EXAMPLE
The first terms, alongside their binary representations, are:
n a(n) bin(a(n))
- ------- ----------------------
1 1 1
2 3 11
3 7 111
4 23 10111
5 151 10010111
6 919 1110010111
7 8087 1111110010111
8 90007 10101111110010111
9 2449303 1001010101111110010111
PROG
(PARI) print1 (v=1); for (n=2, 22, forstep (w=v+s=(b=2)^#digits(v, b), oo, s, if (isprime(w), print1 (", "v=w); break)))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Nov 23 2019
STATUS
approved