digits =: 10&#.^:_1
next =: +/@:!@:digits
loop =: monad define
	n =. next {. y
	if. n e. y do.
		#y
	else.
		loop (n,y)
	end.
)
problem74 =: +/60=loop"0 i.1e6 NB. Takes about a minute to compute