Jelly, 11 bytes
ṗ3’æ."©μÞ‘ċ
How it works
ṗ3’æ."©μÞ‘ċ Main link. Argument: n
ṗ3 Cartesian power; yield all 3-tuples over [1, ..., n].
’ Decrement all coordinates.
"©μÞ‘ Yield [3[6, 69, 20].
æ. Take the dot product of each 3-tuple and [3[6, 69, 20].
ċ Count the occurrences of n (Positive for Chicken McNuggets numbers).
Jelly, 11 bytes
ṗ3’æ."©μÞ‘ċ
How it works
ṗ3’æ."©μÞ‘ċ Main link. Argument: n
ṗ3 Cartesian power; yield all 3-tuples over [1, ..., n].
’ Decrement all coordinates.
"©μÞ‘ Yield [3, 6, 20].
æ. Take the dot product of each 3-tuple and [3, 6, 20].
ċ Count the occurrences of n (Positive for Chicken McNuggets numbers).
Jelly, 11 bytes
ṗ3’æ."©μÞ‘ċ
How it works
ṗ3’æ."©μÞ‘ċ Main link. Argument: n
ṗ3 Cartesian power; yield all 3-tuples over [1, ..., n].
’ Decrement all coordinates.
"©μÞ‘ Yield [6, 9, 20].
æ. Take the dot product of each 3-tuple and [6, 9, 20].
ċ Count the occurrences of n (Positive for Chicken McNuggets numbers).
Jelly, 11 bytes
ṗ3’æ."©μÞ‘ċ
How it works
ṗ3’æ."©μÞ‘ċ Main link. Argument: n
ṗ3 Cartesian power; yield all 3-tuples over [1, ..., n].
’ Decrement all coordinates.
"©μÞ‘ Yield [3, 6, 20].
æ. Take the dot product of each 3-tuple and [3, 6, 20].
ċ Count the occurrences of n (Positive for Chicken McNuggets numbers).
Jelly, 11 bytes
ṗ3’æ."©μÞ‘ċ
How it works
ṗ3’æ."©μÞ‘ċ Main link. Argument: n
ṗ3 Cartesian power; yield all 3-tuples over [1, ..., n].
’ Decrement all coordinates.
"©μÞ‘ Yield [3, 6, 20].
æ. Take the dot product of each 3-tuple and [3, 6, 20].
ċ Count the occurrences of n (Positive for Chicken McNuggets numbers).