# A138728 (b-file synthesized from sequence entry) 1 2 2 3 3 6 4 4 5 7 6 28 7 16 8 31 9 496 10 64 11 127 12 8128 13 4096 14 8191 15 33550336 16 65536 17 131071 18 8589869056 19 262144 20 524287 21 137438691328 22 1073741824 23 2147483647 24 2305843008139952128 25 1152921504606846976 26 2305843009213693951