Adams doesn't say he wasn't influenced by Vonnegut in those quotes.
Also, here's another quote[1]:
> "I've read The Sirens of Titan six times now, and it gets better every time. He is an influence, I must own up. Sirens of Titan is just one of those books – you read it through the first time and you think it's very loosely, casually written. You think the fact that everything suddenly makes such good sense at the end is almost accidental. And then you read it a few more times, simultaneously finding out more about writing yourself, and you realise what an absolute tour de force it was, making something as beautifully honed as that appear so casual."
But I suppose there is a difference between "influenced by" and "trying to emulate" isn't there, and I absolutely should have said the former. They are books that have some similarities, each in their own style.
I didn't inherit this gene, happily for me, and enjoy all three authors a great deal.
If anyone wants to recommend something else in this vein, please do; I'll probably like it.