This sequence is 1, 9, 57, 345, ?. To find the pattern, examine the differences between consecutive terms: 9-1=8, 57-9=48, 345-57=288. These differences (8, 48, 288) follow a pattern where each difference is 6 times the previous difference: 8×6=48, 48×6=288. Therefore, the next difference is 288×6=1728, making the next term 345+1728=2073. Option D is correct.