The man or boy test was proposed by computer scientist Donald Knuth as a means of evaluating implementations of the ALGOL 60 programming language.
The aim of the test was to distinguish compilers that correctly implemented "recursion and non-local references" from those that did not.
[1] There are quite a few ALGOL60 translators in existence which have been designed to handle recursion and non-local references properly, and I thought perhaps a little test-program may be of value.
Trying to work it through on paper is probably fruitless, but for k = 10, the correct answer is −67, despite the fact that in the original article Knuth conjectured it to be −121.
Even modern machines quickly run out of stack space for larger values of k, which are tabulated below (OEIS: A132343).