1,1
The sequence of the corresponding n starts 1, 2, 3, 4, 5, 7, 8, 10, 11, 14, 44, 55, 68, 71, 80, 123, 158, 213, 220, 272, 668, 725, 885, 1132, 1677, 2056, ... [Joerg Arndt, Jul 19 2012]
Vincenzo Librandi, Table of n, a(n) for n = 1..23
Select[Table[3^n+20, {n, 0, 200}], PrimeQ] (* Vincenzo Librandi, Jul 19 2012 *)
(Magma) [ a: n in [0..100] | IsPrime(a) where a is 3^n+20 ]; // Vincenzo Librandi, Jul 19 2012
Cf. A000960.
Sequence in context: A127834 A108111 A085713 * A108249 A338324 A232725
Adjacent sequences: A102901 A102902 A102903 * A102905 A102906 A102907
nonn
Roger L. Bagula, Mar 01 2005
approved