These numbers are always odd and sometimes prime. So far I find (without computer): 1, 7, 119, 2371, 160841, 4824499, 410308643, 16983052531 And n such that the number is prime: 2,4,5 (searched only up to n=8, can’t go further without code). Would someone like to try and find more terms? Thanks, David. Sent from my iPhone