APPLYN

[tboulden]

Using REDUCE makes it easy to recursively compose a LAMBDA with itself.

=LAMBDA(fn,n,
    REDUCE(
        fn,
        SEQUENCE(n-1),
        LAMBDA(composed,ignored,
            LAMBDA(x,composed(fn(x)))
        )
    )
)

LAMBDA_COMPOSE.xlsx
	A	B	C	D
1	Value	n	APPLYN
2	1	10	11
3	1	100	101
4	1	510	511
5	1	511	#NUM!	<-Recursion depth limits still in place
Sheet1

Cell Formulas
Range	Formula
C2:C5	C2	=APPLYN(LAMBDA(x,x+1),B2)(A2)