Comment 1 for bug 1819978

For N = 5000, the list of lists L is ~25 million cons cells, occupying about 400M bytes of memory (on X86-64). If I recall correctly, the default build for sbcl has a maximum heap size of 500M. So it shouldn't be surprising you've run out of memory here, since GC needs some room for copying.

You aren't seeing this because your call to TIME does not include the loops where you are building L.

You can rebuild sbcl with a large heap size by specifying the --dynamic-space-size argument in the build script.