4. Augmented amicable numbers

Search program for augmented amicable number

The definition of augmented amicable numbers is,

σ(m)=σ(n)=m+n-1

and the program can be used in trivial change,

30   N=fnSigma(M)-M-1:if N<=M then 50
40   R=fnSigma(N)-N-1:if R=M then print M,N

into

30   N=fnSigma(M)-M+1:if N<=M then 50
40   R=fnSigma(N)-N+1:if R=M then print M,N

  There are 420 augmented amicable pairs which smaller number is less than 10¹⁰.