OFFSET
1,1
COMMENTS
Is the sequence finite?
The last term appears to be 5833497. - T. D. Noe, Nov 23 2004
A less strict version of A039669, n - 2^k is prime for 0 < k < log_2 k. If a number is in that sequence, then obviously it is also in this sequence. As of this writing, 105 is believed to be the last term of that sequence. - Alonso del Arte, May 24 2017
LINKS
T. D. Noe, Table of n, a(n) for n=1..102 (no others < 2*10^9)
EXAMPLE
167 is a term as 167 - 4 = 163, 167 - 16 = 151, 167 - 64 = 103 are primes.
MAPLE
filter:= proc(n) local k, t;
for k from 1 do
if 4^k >= n-1 then return true
elif not isprime(n-4^k) then return false
fi
od
end proc:
select(filter, [$5..3000]); # Robert Israel, May 24 2017
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Feb 17 2002
EXTENSIONS
More terms from Sascha Kurz, Mar 19 2002
STATUS
approved