# A137787 (b-file synthesized from sequence entry) 0 -2 1 -4 2 -4 3 26 4 272 5 1826 6 10736 7 59426 8 318272 9 1670786 10 8656976 11 44454626 12 226827872 13 1151991746 14 5830280816 15 29429454626 16 148249811072 17 745630312706 18 3745590106256 19 18797445635426 20 94264432179872 21 472428649241666 22 2366562219717296 23 11850466059333026 24 59322887352366272