My source for this is the latest 10-year Economic Projection (from June 2024). This is their data through 2034, except I rounded it to the nearest 100 billion. They are using 3.8% as a long term growth factor, so after 2034, the numbers increase each year that. This only runs through 2054 because it is pointless to project out further, even though it is fun to do so. You could plug these numbers into my deficit forecasting model, since most of those are based on percents of GDP.
2024 28,500
2025 29,700
2026 30,900
2027 32,000
2028 33,100
2029 34,300
2030 35,700
2031 37,000
2032 38,400
2033 39,900
2034 41,400
2035 43,000
2036 44,600
2037 46,300
2038 48,100
2039 49,900
2040 51,800
2041 53,800
2042 55,800
2043 57,900
2044 60,100
2045 62,400
2046 64,800
2047 67,300
2048 69,900
2049 72,600
2050 75,400
2051 78,300
2052 81,300
2053 84,400
2054 87,600
See also
https://aftermath2022.blogspot.com/2024/01/projected-nominal-gdp-through-2100.html for a more optimistic forecast.