For the record, here is the page order to print a brochure (A5 booklet) from a A4/letter documents (2 pages per sheet, landscape orientation, with short-edge border if in duplex mode). It might be applied to staroffice/openoffice/libreoffice, ms-word, and PDF documents.

  • 1-4 pages

single: 4,1 / 2,3
reverse: 4,1 / 2,3
duplex: 4,1,2,3

  • 5-8 pages

single: 8,1,6,3 / 2,7,4,5
reverse: 8,1,6,3 / 4,5,2,7
duplex: 8,1,2,7,6,3,4,5

  • 9-12 pages

single: 12,1,10,3,8,5 / 2,11,4,9,6,7
reverse: 12,1,10,3,8,5 / 6,7,4,9,2,11
duplex: 12,1,2,11,10,3,4,9,8,5,6,7

  • 13-16 pages

single: 16,1,14,3,12,5,10,7 / 2,15,4,13,6,11,8,9
reverse: 16,1,14,3,12,5,10,7 / 8,9,6,11,4,13,2,15
duplex: 16,1,2,15,14,3,4,13,12,5,6,11,10,7,8,9

  • 17-20 pages

single: 20,1,18,3,16,5,14,7,12,9 / 2,19,4,17,6,15,8,13,10,11
reverse: 20,1,18,3,16,5,14,7,12,9 / 10,11,8,13,6,15,4,17,2,19
duplex: 20,1,2,19,18,3,4,17,16,5,6,15,14,7,8,13,12,9,10,11

  • 21-24 pages

single: 24,1,22,3,20,5,18,7,16,9,14,11 / 2,23,4,21,6,19,8,17,10,15,12,13
reverse: 24,1,22,3,20,5,18,7,16,9,14,11 / 12,13,10,15,8,17,6,19,4,21,2,23
duplex: 24,1,2,23,22,3,4,21,20,5,6,19,18,7,8,17,16,9,10,15,14,11,12,13

  • 25-28 pages

single: 28,1,26,3,24,5,22,7,20,9,18,11,16,13 / 2,27,4,25,6,23,8,21,10,19,12,17,14,15
reverse: 28,1,26,3,24,5,22,7,20,9,18,11,16,13 / 14,15,12,17,10,19,8,21,6,23,4,25,2,27
duplex: 28,1,2,27,26,3,4,25,24,5,6,23,22,7,8,21,20,9,10,19,18,11,12,17,16,13,14,15

  • 29-32 pages

single: 32,1,30,3,28,5,26,7,24,9,22,11,20,13,18,15 / 2,31,4,29,6,27,8,25,10,23,12,21,14,19,16,17
reverse: 32,1,30,3,28,5,26,7,24,9,22,11,20,13,18,15 / 16,17,14,19,12,21,10,23,8,25,6,27,4,29,2,31
duplex: 32,1,2,31,30,3,4,29,28,5,6,27,26,7,8,25,24,9,10,23,22,11,12,21,20,13,14,19,18,15,16,17