In these and in the tens, the kai is frequently omitted, though not in triskaidekaphobia.
From the en.wikipedia.org
Theories span the map on the origins of triskaidekaphobia.
From the 6thfloor.blogs.nytimes.com
Version 13 was likely skipped due to a superstitious aversion to the number thirteen, known as triskaidekaphobia.
From the en.wikipedia.org
The superstitious sufferers of triskaidekaphobia try to avoid bad luck by keeping away from anything numbered or labelled thirteen.
From the en.wikipedia.org
The latest frequency tables for the British lottery numbers reveal visible statistical evidence of naturally occurring triskaidekaphobia.
From the newscientist.com
For those of you who suffer from friggatriskaidekaphobia, the fear of Friday the 13th, or triskaidekaphobia, the fear of the number 13, today is the only Friday the 13th this year.
From the orlandosentinel.com
He adds that triskaidekaphobia, or fear of 13, appears to be fading, with floors labeled 13 in Marc properties showing occupancy rates are no lower than other floors.
From the online.wsj.com
More examples
A morbid fear of the number 13
(triskaidekaphobic) suffering from triskaidekaphobia (abnormal fear of the number 13)