The seat map of 777-300ER (77A) description is listed below, as per Amadeus:

First Class

1A 1D 1K
2A 2D 2K

*2K is marked with C (COT)

Business Class

11A 11D11G 11K
12A 12D12G 12K
15A 15D15G 15K
16A 16D16G 16K
:::: :::::::: ::::
:::: :::::::: ::::
26A 26D26G 26K
27A ***** 27K

*No Row 13/14, nor 26D/26G
*Entire Row 11 marked as Last Offered
*15ADG, 16C marked with C (COT)
*Row 15-27 is located at the wing

Economy Class
******* 30D30E30G ********
31A31B31C 31D31E31G 31H31J31K
32A32B32C 32D32E32G 32H32J32K
:::::::::::: :::::::::::: ::::::::::::
:::::::::::: :::::::::::: ::::::::::::
43A43B43C 43D43E43G 43H43J43K
44A44B44C ******** ********
_______ ____ ______
54A54B54C ******** 54H54J54K
55A55B55C 55D55E55G 55H55J55K
56A56B56C 56D56E56G 56H56J56K
:::::::::::: :::::::::::: ::::::::::::
:::::::::::: :::::::::::: ::::::::::::
65A65B65C 65D65E65G 65H65J65K
66A***66C 66D66E66G 66H***66K
67A***67C 67D67E67G 67H***67K

*No Row 45-53
*No Seats: 30ABCHJK, 44DEGHJK, 54DEG
*Seats marked last offered: 30DEG, 31ABCHJK, 55DEG, 65ABCHJK, 66ACHK, 67ACHK
*Seats marked with C (COT): 30DEG, 55DEG
*Wing section spans to Row 37


:::::: represents subsequent rows. saving time to type all the seat numbers
*** represents no seats