add+together
131Perfect totient number — In number theory, a perfect totient number is an integer that is equal to the sum of its iterated totients. That is, we apply the totient function to a number n , apply it again to the resulting totient, and so on, until the number 1 is reached,… …
132superpositionprinciple — superposition principle n. A principle holding that certain waves or functions can add together when overlapped to form a new wave or function and then return to their original states when separated. * * * …
