OFFSET
2,2
COMMENTS
An easily computed sequence, growing faster than linearly, that provably contains infinitely many primes.
LINKS
Robert Israel, Table of n, a(n) for n = 2..10000
R. Israel, Answer to "What's the fastest growing function known to contain infinitely many primes?", Mathematics StackExchange.
FORMULA
G.f.: x^2/(1-x)^2 + Sum_{m>=1} (7*2^(3*m-3)-3*2^(2*m-1))*x^(2*4^m)/(1-x).
MAPLE
f:= proc(n) local m, j;
m:= floor(log[4](n/2));
2^(3*m)+n - 2^(2*m+1)
end proc:
map(f, [$2..100]); # Robert Israel, Jan 25 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Robert Israel, Jan 25 2018
STATUS
approved