The first critical question is: did he have a will? If there was a will, only the people named in it inherit, regardless of their relationship--unless a category of relationship is named, in which case all persons of that relationship inherit. So if had a will saying that he left his estate in equal shares to his "children," then you, as one of his children, would inherit. On the other hand, say that the will said that he leaves his estate to his wife, Jane Roe, or to his children, John and James Doe. In that case, since specific persons are named and you are not one of them, you would not inherit.
If there is no will, then since you are his child but not by his current spouse, you will inherit, with the exact amount depending on whether he has a surviving spouse and other surviving children (and if other children, how many of them). The fewer other people to inherit, the larger your share.
The above presumes you could prove that you are his child, such as by a DNA test.
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