# A077821 (b-file synthesized from sequence entry) 0 1 1 4 2 16 3 64 4 253 5 1000 6 3952 7 15616 8 61705 9 243820 10 963424 11 3806848 12 15042277 13 59437648 14 234860320 15 928020736 16 3666956113 17 14489511508 18 57253465072 19 226229798080 20 893918323981 21 3532204761400 22 13957058650384 23 55149545207296 24 217916425857241 25 861069089144764