# A024960 (b-file synthesized from sequence entry) 1 1 2 2 3 5 4 12 5 28 6 66 7 172 8 440 9 1108 10 2784 11 7552 12 20040 13 52336 14 136896 15 374688 16 1013056 17 2710016 18 7243104 19 20078784 20 55031040 21 149414144 22 405759232 23 1130565632 24 3125798656 25 8582582272 26 23543099392 27 66051398144 28 183922571264 29 508945206272