## 2. Amicable numbers

### Search program for amicable numbers

Using fnSigma(N) subroutine, we try to find amicable numbers
up to smaller number less than 10^{10}.

10 '
20 for M=2 to 10^9
30 N=fnSigma(M)-M:if N<=M then 50
40 R=fnSigma(N)-N:if R=M then print M,N
50 next M
60 end
70 fnSigma(N)
80 local W,S,P
90 S=1
100 W=1:P=prmdiv(N)
110 if N@P=0 then W=W*P+1:N=N\P:goto 110 else S=S*W
120 if N>1 then 100 else return(S)

The "if" condition in the line 30 is the rule for omitting perfect numbers.

There are **1427** amicable pairs which smaller number is less than 10^{10}.

E-mail : kc2h-msm@asahi-net.or.jpHisanori Mishima