login
Nonsquare, composite numbers k such that Sum_{d|k, d < k/d} s_d = k+1, where s_d is either d+1/(k/d) or (1/d)+(k/d).
0

%I #12 May 20 2023 03:23:21

%S 42,48,60,72,120,132,216,240,264,312,330,360,396,420,432,440,448,456,

%T 480,504,528,540,546,560,600,612,620,630,648,672,684,700,704,720,756,

%U 768,780,792,810,812,840,864,924,936,960,990,1008,1020,1040,1050,1056

%N Nonsquare, composite numbers k such that Sum_{d|k, d < k/d} s_d = k+1, where s_d is either d+1/(k/d) or (1/d)+(k/d).

%e 42 is in the sequence because 1+(1/42) + (1/2)+21 + (1/3)+14 + 6+(1/7) = 42+1.

%e 48 is in the sequence because 1+(1/48) + (1/2)+24 + 3+(1/16) + (1/4)+12 + (1/6)+8 = 48+1.

%K nonn

%O 1,1

%A _Naohiro Nomoto_, Sep 06 2001

%E More terms from _Sascha Kurz_, Feb 02 2003

%E Offset corrected by _Mohammed Yaseen_, May 20 2023