On page 196 of "just After Sunset" in the short story N. the OCD pateint is describing his counting problem and mentions the number 19. mentions it to be a powerful and bad number.

"Divide 3728 by two and you come out with eighteen-hundred-and-sixtyfour. 1864 adds up to nineteen, a powerful odd number. powerful and bad."-just after sunset

What N. sees in Ackermans Field could be a speaking circle. He talks about the field seeming thin, like at any moment things from other universes could come spilling out.

the monster cthun coming out of the ring of stones and the mention of other worlds