OFFSET
0,3
EXAMPLE
a(0) = 1 because 2^(0 - 0) + 3^0 = 2^0 + 1 = 1 + 1 = 2 is prime.
MATHEMATICA
a[n_]:=Length[Select[Range[0, n], PrimeQ[2^(n-#)+3^#] &]]; Array[a, 101, 0] (* Stefano Spezia, Sep 22 2024 *)
PROG
(Magma) [#[k: k in [0..n] | IsPrime(2^(n-k)+3^k)]: n in [0..100]];
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Sep 20 2024
STATUS
approved