Macro Confusion @.@
Long answer: Don't macro that. Even as a castsequence it will result in failure. As a fire mage you're primarily casting five spells: Living Bomb, Inferno Blast, Combustion, Pyroblast and Fireball. The cooldowns of Inferno Blast and Combustion do not line up. The duration of Living Bomb and the cooldown of Inferno Blast do not line up either. A castsequence of those abilities would result in a huge loss in dps.
I would suggest you take advantage of modifier macros. You can easily put the core fire abilities on 3 buttons.
/cast [mod:alt] Combustion; Pyroblast
/cast [mod:alt] Flamestrike; Fireball
/cast [mod:alt] Living Bomb; Inferno Blast
You should be able to put those macros into action buttons 2-4 and use your thumb to toggle the Left Alt key. You may not like it at first, but modifier keys are important for getting all your abilities onto your action bar.
Please report any Code of Conduct violations, including:
Threats of violence. We take these seriously and will alert the proper authorities.
Posts containing personal information about other players. This includes physical addresses, e-mail addresses, phone numbers, and inappropriate photos and/or videos.
Harassing or discriminatory language. This will not be tolerated.